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Sample records for macrophomina phaseolina propagules

  1. Meios de cultura semi-seletivos para Macrophomina phaseolina

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    Selma Rogéria de Carvalho Nascimento

    2014-12-01

    Full Text Available Macrophomina phaseolina (Tassi Golidanich é um fungo habitante do solo importante economicamente devido ao amplo número de espécies de plantas que infectam e da dificuldade do seu controle. Vários estudos envolvendo densidade de inóculo, taxonomia, sobrevivência, necessitam de meios de cultura seletivo ou semi-seletivo. O objetivo do trabalho foi avaliar 16 meios de cultura quanto à especificidade a este patógeno, proporcionando maior porcentagem de detecção do seu crescimento e menor número de contaminações, para substituir o meio semi-seletivo RB modificado, rotineiramente utilizado em estudos deste patógeno. O meio semi-seletivo RB modificado é bastante eficiente e contém em sua composição o fungicida metalaxyl (inibidor de oomycetos, que atualmente não se encontra disponível comercialmente em formulação simples, sem adição do Mancozeb ou Clorotalonil que inibem o crescimento do fungo M. phaseolina. Os meios de cultura avaliados foram repicados com o inóculo do fungo produzido em substrato areno-orgânico, contido em bolsas de náilon, recuperados após 30 dias de um solo não autoclavado, contido em uma bandeja. Cada meio de cultura avaliado tiveram 7 repetições, representadas por uma placa de Petri. Para as comparações das médias das porcentagens do crescimento de M. phaseolina e do número de contaminantes foi utilizado o teste de Scott-knott a 5% de probabilidade e os valores em porcentagem foram transformados em arc sem (√/100. Dentre os meios de cultura avaliados os MSTP 1 [(BDA com tetraciclina 50 mg.L-1 mais propamocarb a 1 mL.L-1(Previcur N® 72,2% p.a.], MSRP 0,5 (BDA com rifampicina 100 mg.L-1 mais fungicida propamocarb a 0,5 mL.L-1 e MSRP 1 (BDA com rifampicina 100 mg.L-1 mais fungicida propamocarb a 1 mL.L-1 proporcionaram maior porcentagem e detecção do fungo M. phaseolina e menor número de contaminações por outros fungos e bactérias. Estes meios de cultura semi-seletivos podem ser

  2. Host Specialization in the Charcoal Rot Fungus, Macrophomina phaseolina.

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    Su, G; Suh, S O; Schneider, R W; Russin, J S

    2001-02-01

    ABSTRACT To investigate host specialization in Macrophomina phaseolina, the fungus was isolated from soybean, corn, sorghum, and cotton root tissue and soil from fields cropped continuously to these species for 15 years in St. Joseph, LA. Chlorate phenotype of each isolate was determined after growing on a minimal medium containing 120 mM potassium chlorate. Consistent differences in chlorate sensitivity were detected among isolates from different hosts and from soil versus root. To further explore genetic differentiation among fungal isolates from each host, these isolates were examined by restriction fragment length polymorphism and random amplified polymorphic DNA (RAPD) analysis. No variations were observed among isolates in restriction patterns of DNA fragments amplified by polymerase chain reaction covering the internal transcribed spacer region, 5.8S rRNA and part of 25S rRNA, suggesting that M. phaseolina constitutes a single species. Ten random primers were used to amplify the total DNA of 45 isolates, and banding patterns resulting from RAPD analysis were compared with the neighbor-joining method. Isolates from a given host were genetically similar to each other but distinctly different from those from other hosts. Chlorate-sensitive isolates were distinct from chlorate-resistant isolates within a given host. In greenhouse tests, soybean, sorghum, corn, and cotton were grown separately in soil infested with individual isolates of M. phaseolina that were chosen based on their host of origin and chlorate phenotype. Root colonization and plant weight were measured after harvesting. More colonization of corn roots occurred when corn was grown in soil containing corn isolates compared with isolates from other hosts. However, there was no host specialization in isolates from soybean, sorghum, or cotton. More root colonization in soybean occurred with chlorate-sensitive than with chlorate-resistant isolates.

  3. Screening brazilian macrophomina phaseolina isolates for alkaline lipases and other extracellular hydrolases

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    Schinke, Cláudia; Germani, Jose Carlos

    2012-01-01

    Macrophomina phaseolina, phylum Ascomycota, is a phytopathogenic fungus distributed worldwide in hot dry areas. There are few studies on its secreted lipases and none on its colony radial growth rate, an indicator of fungal ability to use nutrients for growth, on media other than potato-dextrose agar. In this study, 13 M. phaseolina isolates collected in different Brazilian regions were screened for fast-growth and the production of hydrolases of industrial interest, especially alkaline lipas...

  4. Genetic Architecture of Charcoal Rot (Macrophomina phaseolina) Resistance in Soybean Revealed Using a Diverse Panel

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    Charcoal rot disease caused by Macrophomina phaseolina is responsible for significant yield losses in soybean production. Among the methodologies available for controlling this disease, breeding for resistance is the most promising. Progress in breeding efforts has been slow due to the insufficient ...

  5. Molecular Identification and Genetic Characterization of Macrophomina phaseolina Strains Causing Pathogenicity on Sunflower and Chickpea

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    Ali N. Khan

    2017-07-01

    Full Text Available Macrophomina phaseolina is the most devastating pathogen which causes charcoal rot and root rot diseases in various economically important crops. Three strains M. phaseolina 1156, M. phaseolina 1160, and M. phaseolina PCMC/F1 were tested for their virulence on sunflower (Helianthus annuus L. and chickpea (Cicer arietinum L.. The strains showed high virulence on both hosts with a disease score of 2 on chickpea and sunflower. The strains also increased the hydrogen per oxide (H2O2 content by 1.4- to 1.6-fold in root as well as shoot of chickpea and sunflower. A significant increase in antioxidant enzymes was observed in fungal infected plants which indicated prevalence of oxidative stress during pathogen propagation. The M. phaseolina strains also produced hydrolytic enzymes such as lipase, amylase, and protease with solubilization zone of 5–43 mm, 5–45 mm, and 12–35 mm, respectively. The M. phaseolina strains were identified by 18S rRNA and analyzed for genetic diversity by using random amplified polymorphic DNA (RAPD markers. The findings based on RAPD markers and 18S rRNA sequence analysis clearly indicate genetic variation among the strains collected from different hosts. The genetically diverse strains were found to be pathogenic to sunflower and chickpea.

  6. Tools to kill: Genome of one of the most destructive plant pathogenic fungi Macrophomina phaseolina

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    Islam Md

    2012-09-01

    Full Text Available Abstract Background Macrophomina phaseolina is one of the most destructive necrotrophic fungal pathogens that infect more than 500 plant species throughout the world. It can grow rapidly in infected plants and subsequently produces a large amount of sclerotia that plugs the vessels, resulting in wilting of the plant. Results We sequenced and assembled ~49 Mb into 15 super-scaffolds covering 92.83% of the M. phaseolina genome. We predict 14,249 open reading frames (ORFs of which 9,934 are validated by the transcriptome. This phytopathogen has an abundance of secreted oxidases, peroxidases, and hydrolytic enzymes for degrading cell wall polysaccharides and lignocelluloses to penetrate into the host tissue. To overcome the host plant defense response, M. phaseolina encodes a significant number of P450s, MFS type membrane transporters, glycosidases, transposases, and secondary metabolites in comparison to all sequenced ascomycete species. A strikingly distinct set of carbohydrate esterases (CE are present in M. phaseolina, with the CE9 and CE10 families remarkably higher than any other fungi. The phenotypic microarray data indicates that M. phaseolina can adapt to a wide range of osmotic and pH environments. As a broad host range pathogen, M. phaseolina possesses a large number of pathogen-host interaction genes including those for adhesion, signal transduction, cell wall breakdown, purine biosynthesis, and potent mycotoxin patulin. Conclusions The M. phaseolina genome provides a framework of the infection process at the cytological and molecular level which uses a diverse arsenal of enzymatic and toxin tools to destroy the host plants. Further understanding of the M. phaseolina genome-based plant-pathogen interactions will be instrumental in designing rational strategies for disease control, essential to ensuring global agricultural crop production and security.

  7. Tools to kill: genome of one of the most destructive plant pathogenic fungi Macrophomina phaseolina.

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    Islam, Md Shahidul; Haque, Md Samiul; Islam, Mohammad Moinul; Emdad, Emdadul Mannan; Halim, Abdul; Hossen, Quazi Md Mosaddeque; Hossain, Md Zakir; Ahmed, Borhan; Rahim, Sifatur; Rahman, Md Sharifur; Alam, Md Monjurul; Hou, Shaobin; Wan, Xuehua; Saito, Jennifer A; Alam, Maqsudul

    2012-09-19

    Macrophomina phaseolina is one of the most destructive necrotrophic fungal pathogens that infect more than 500 plant species throughout the world. It can grow rapidly in infected plants and subsequently produces a large amount of sclerotia that plugs the vessels, resulting in wilting of the plant. We sequenced and assembled ~49 Mb into 15 super-scaffolds covering 92.83% of the M. phaseolina genome. We predict 14,249 open reading frames (ORFs) of which 9,934 are validated by the transcriptome. This phytopathogen has an abundance of secreted oxidases, peroxidases, and hydrolytic enzymes for degrading cell wall polysaccharides and lignocelluloses to penetrate into the host tissue. To overcome the host plant defense response, M. phaseolina encodes a significant number of P450s, MFS type membrane transporters, glycosidases, transposases, and secondary metabolites in comparison to all sequenced ascomycete species. A strikingly distinct set of carbohydrate esterases (CE) are present in M. phaseolina, with the CE9 and CE10 families remarkably higher than any other fungi. The phenotypic microarray data indicates that M. phaseolina can adapt to a wide range of osmotic and pH environments. As a broad host range pathogen, M. phaseolina possesses a large number of pathogen-host interaction genes including those for adhesion, signal transduction, cell wall breakdown, purine biosynthesis, and potent mycotoxin patulin. The M. phaseolina genome provides a framework of the infection process at the cytological and molecular level which uses a diverse arsenal of enzymatic and toxin tools to destroy the host plants. Further understanding of the M. phaseolina genome-based plant-pathogen interactions will be instrumental in designing rational strategies for disease control, essential to ensuring global agricultural crop production and security.

  8. Antibiosis of Trichoderma spp strains native to northeastern Mexico against the pathogenic fungus Macrophomina phaseolina

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    Mendoza, José Luis Hernández; Pérez, María Isabel Sánchez; Prieto, Juan Manuel González; Velásquez, Jesús DiCarlo Quiroz; Olivares, Jesús Gerardo García; Langarica, Homar Rene Gill

    2015-01-01

    Abstract Sampling of agricultural soils from the Mexican northeastern region was performed to detect Trichoderma spp., genetically characterize it, and assess its potential use as a biologic control agent against Macrophomina phaseolina. M. phaseolina is a phytopathogen that attacks over 500 species of cultivated plants and causes heavy losses in the regional sorghum crop. Sampling was performed immediately after sorghum or corn harvest in an area that was approximately 170 km from the Mexico-USA border. Sixteen isolates were obtained in total. Using colony morphology and sequencing the internal transcribed spacers (ITS) 1 and 4 of 18S rDNA, 14 strains were identified as Trichoderma harzianum, T. koningiopsis and T. virens. Subsequently, their antagonistic activity against M. phaseolina was evaluated in vitro, and 11 isolates showed antagonism by competition and stopped M. phaseolina growth. In 4 of these isolates, the antibiosis phenomenon was observed through the formation of an intermediate band without growth between colonies. One strain, HTE808, was identified as Trichoderma koningiopsis and grew rapidly; when it came into contact with the M. phaseolina colony, it continued to grow and sporulated until it covered the entire petri dish. Microscopic examination confirmed that it has a high level of hyperparasitism and is thus considered to have high potential for use in the control of this phytopathogen. PMID:26691467

  9. Characterization of Macrophomina phaseolina isolates by their response to different osmotic potentials and AFLP

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    Bárbara J. Gutiérrez Cedeño

    2014-01-01

    Full Text Available Charcoal rot of Phaseolus vulgaris is caused by the fungus Macrophomina phaseolina, the disease is associated with high temperature and water stress. The objective of this study was to characterize isolates of M. phaseolina by their response to different osmotic potentials and AFLP. The growth of 11 isolates was determined on potato dextrose agar at 48 and 72 h in a gradient of osmotic potential induced using NaCl as well as their effects on germination of sclerotia. Three water groups were statistically different indicating differential response to osmotic potential and all sclerotia grown under these conditions, germinated between 24 and 48h. There were groups of isolates that were tolerant to water stress induced. The AFLP genotyping allowed the formation of five genetic groups, showing a wide genetic variability. Of the nine starters CTA-AT showed a high degree of confidence in the identification of genotypes of M. phaseolina and CAA-AC had the lowest discriminatory power. These results show that M. phaseolina isolates responded differently to osmotic potential and are genetically different between them. Although there was a clear correspondence of genetic groups to water groups; these responses are important features in the search for alternative management in black bean pathosystem. Keywords: molecular marker, M. phaseolina, water deficit

  10. Ectopic Expression of JcWRKY Confers Enhanced Resistance in Transgenic Tobacco Against Macrophomina phaseolina.

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    Agarwal, Parinita; Patel, Khantika; Agarwal, Pradeep K

    2018-04-01

    Plants possess an innate immune system comprising of a complex network of closely regulated defense responses involving differential gene expression mediated by transcription factors (TFs). The WRKYs comprise of an important plant-specific TF family, which is involved in regulation of biotic and abiotic defenses. The overexpression of JcWRKY resulted in improved resistance in transgenic tobacco against Macrophomina phaseolina. The production of reactive oxygen species (ROS) and its detoxification through antioxidative system in the transgenics facilitates defense against Macrophomina. The enhanced catalase activity on Macrophomina infection limits the spread of infection. The transcript expression of antioxidative enzymes gene (CAT and SOD) and salicylic acid (SA) biosynthetic gene ICS1 showed upregulation during Macrophomina infection and combinatorial stress. The enhanced transcript of pathogenesis-related genes PR-1 indicates the accumulation of SA during different stresses. The PR-2 and PR-5 highlight the activation of defense responses comprising of activation of hydrolytic cleavage of glucanases and thaumatin-like proteins causing disruption of fungal cells. The ROS homeostasis in coordination with signaling molecules regulate the defense responses and inhibit fungal growth.

  11. Effects of compost amendment and the biocontrol agent Clonostachys rosea on the development of charcoal rot (Macrophomina phaseolina) on cowpea

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    Ndiaye, M.; Termorshuizen, A.J.; Bruggen, van A.H.C.

    2010-01-01

    Macrophomina phaseolina is a destructive pathogen causing charcoal rot of cowpea and other crops in the semi- arid areas of the Sahel (north-west Africa). Chemical management is not feasible in conditions of subsistence farming, and the plurivorous nature of the fungus limits the effectiveness of

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

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

    1994-12-01

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

  13. Recovery of Extracellular Lipolytic Enzymes from Macrophomina phaseolina by Foam Fractionation with Air

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    Claudia Schinke

    2013-01-01

    Full Text Available Macrophomina phaseolina was cultivated in complex and simple media for the production of extracellular lipolytic enzymes. Culture supernatants were batch foam fractionated for the recovery of these enzymes, and column design and operation included the use of P 2 frit (porosity 40 to 100 μm, air as sparging gas at variable flow rates, and Triton X-100 added at the beginning or gradually in aliquots. Samples taken at intervals showed the progress of the kinetic and the efficiency parameters. Best results were obtained with the simple medium supernatant by combining the stepwise addition of small amounts of the surfactant with the variation of the air flow rates along the separation. Inert proteins were foamed out first, and the subsequent foamate was enriched in the enzymes, showing estimated activity recovery (R, enrichment ratio (E, and purification factor (P of 45%, 34.7, and 2.9, respectively. Lipases were present in the enriched foamate.

  14. Product optimization, purification and characterization of a novel polygalacturonase produced by Macrophomina phaseolina

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    Saeed Aminzadeh

    2013-01-01

    Full Text Available Introduction: Production of a novel polygalacturonase (PG active at pH = 3.0 and suitable to be used in fruit juice industries from Macrophomina phaseolina was evaluated. Suitable carbon, nitrogen and phosphorous forms were determined and the condition was optimized for higher PG production. Materials and methods: Macrophomina phaseolina was cultured in so called production medium. The secretome was separated from fungal cells and polygalacturonase was isolated via column chromatography. The biochemical activity of both secretome and isolated polygalacturonase were assayed calorimetrically. The production of polygalacturonase was optimized via changes in culture medium in terms of contents, pH and temperature and Taguchi analysis of data. Enzyme kinetics was partially performed followed by the determination of pH and temperature stability. Results: A range of sugars except glucose and chitin demonstrated to improve the PG production. Ammonium sulfate and peptone demonstrated to be suitable nitrogen sources. Amongst phosphorous sources, dipotassium hydrogen phosphate had the greatest effect. Taguchi’s orthogonal array demonstrated that pH, temperature, ammonium sulfate and trace elements had significant effect on PG production. Furthermore, mean comparisons showed that the optimum condition achieved at pH 6.0, 35 °C, 2 g.l-1 ammonium sulfate and 2 mg.l-1 trace elements. Discussion and conclusion: The purified PG with a relative molecular mass of 70 kDa was demonstrated its highest activity at pH = 3, and 30 °C. Amongst tested cations and chemicals, Fe2+ improved the enzyme activity by 2 fold, while the secretome responded differently.

  15. Screening Brazilian Macrophomina phaseolina isolates for alkaline lipases and other extracellular hydrolases.

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    Schinke, Claudia; Germani, José C

    2012-03-01

    Macrophomina phaseolina, phylum Ascomycota, is a phytopathogenic fungus distributed worldwide in hot dry areas. There are few studies on its secreted lipases and none on its colony radial growth rate, an indicator of fungal ability to use nutrients for growth, on media other than potato-dextrose agar. In this study, 13 M. phaseolina isolates collected in different Brazilian regions were screened for fast-growth and the production of hydrolases of industrial interest, especially alkaline lipases. Hydrolase detection and growth rate determination were done on citric pectin, gelatin, casein, soluble starch, and olive oil as substrates. Ten isolates were found to be active on all substrates tested. The most commonly detected enzymes were pectinases, amylases, and lipases. The growth rate on pectin was significantly higher (P media identified CMM 2105, CMM 1091, and PEL as the fastest-growing isolates. The lipase activity of four isolates grown on olive oil was followed for 4 days by measuring the activity in the cultivation broth. The specific lipolytic activity of isolate PEL was significantly higher at 96 h (130 mU mg protein(-1)). The broth was active at 37 °C, pH 8, indicating the potential utility of the lipases of this isolate in mild alkaline detergents. There was a strong and positive correlation (0.86) between radial growth rate and specific lipolytic activity.

  16. A combination of biocontrol agents improves the management of dry root rot (Macrophomina phaseolina in greengram

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    R. Thilagavathi

    2007-08-01

    Full Text Available The biocontrol agents Trichoderma viride (strains Tv1 and Tv13, Pseudomonas fluorescens (Pf1 and Py15 and Bacillus subtilis (Bs16 were tested individually and in combination for their effectiveness against root rot of greengram caused by Macrophomina phaseolina. As regards the compatibility of the biocontrol agents with each other, T. viride strains were not compatible with B. subtilis (Bs16, but P. fluorescens strains were compatible with B. subtilis and T. viride. Of the biocontrol agents tested in vitro against M. phaseolina, combinations of P. fluorescens+T. viride (Pf1+Tv1, Pf1+Tv13 and Py15+Tv1 inhibited mycelial growth of the pathogen and they also promoted the growth of the greengram seedlings. A combination of Pf1+Tv1 was most effective in reducing root rot incidence under glass-house and field conditions as compared with other single or combined treatments or the untreated control. The activity of the defense-related enzymes peroxidase, polyphenol oxidase and phenyl alanine ammonia lyase was significantly greater in greengram plants treated with a talc based formulation containing Pf1+Tv1 followed by Pf1+Tv13 and Py15+Tv1, than in plants receiving other treatments or the untreated control. Moreover, a combination of Pf1+Tv1 followed by Pf1+Tv13 and Py15+Tv1 significantly increased yield under glass house and field conditions.

  17. Relatedness of Macrophomina phaseolina isolates from tallgrass prairie, maize, soybean and sorghum.

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    Saleh, A A; Ahmed, H U; Todd, T C; Travers, S E; Zeller, K A; Leslie, J F; Garrett, K A

    2010-01-01

    Agricultural and wild ecosystems may interact through shared pathogens such as Macrophomina phaseolina, a generalist clonal fungus with more than 284 plant hosts that is likely to become more important under climate change scenarios of increased heat and drought stress. To evaluate the degree of subdivision in populations of M. phaseolina in Kansas agriculture and wildlands, we compared 143 isolates from maize fields adjacent to tallgrass prairie, nearby sorghum fields, widely dispersed soybean fields and isolates from eight plant species in tallgrass prairie. Isolate growth phenotypes were evaluated on a medium containing chlorate. Genetic characteristics were analysed based on amplified fragment length polymorphisms and the sequence of the rDNA-internal transcribed spacer (ITS) region. The average genetic similarity was 58% among isolates in the tallgrass prairie, 71% in the maize fields, 75% in the sorghum fields and 80% in the dispersed soybean fields. The isolates were divided into four clusters: one containing most of the isolates from maize and soybean, two others containing isolates from wild plants and sorghum, and a fourth containing a single isolate recovered from Solidago canadensis in the tallgrass prairie. Most of the sorghum isolates had the dense phenotype on media containing chlorate, while those from other hosts had either feathery or restricted phenotypes. These results suggest that the tallgrass prairie supports a more diverse population of M. phaseolina per area than do any of the crop species. Subpopulations show incomplete specialization by host. These results also suggest that inoculum produced in agriculture may influence tallgrass prairie communities, and conversely that different pathogen subpopulations in tallgrass prairie can interact there to generate 'hybrids' with novel genetic profiles and pathogenic capabilities.

  18. The effect of UV and visible light irradiation on the development of microsclerotium of the fungus Macrophomina phaseolina

    International Nuclear Information System (INIS)

    Nagy, P.; Fischl, G.

    2002-01-01

    Macrophomina phaseolina is a poliphagus fungus, which is able to infect numerous host-plant (maize, sunflower, pepper) and causes large yield losses. Our in vitro experiments demonstrate, how different wavelength light irradiation influences the growth of mycelium and the formation of microsclerotium. The habit of cultures treated by blue light and UV radiation changed, the formed microsclerotia had a convenient sharpness for the data evaluation by CCD camera. The mycelium was degraded as a result of UV radiation

  19. Diallel crosses for resistance to Macrophomina phaseolina and Thanatephorus cucumeris on cowpea.

    Science.gov (United States)

    Lima, L R L; Damasceno-Silva, K J; Noronha, M A; Schurt, D A; Rocha, M M

    2017-09-27

    This study aimed at identifying and selecting through partial diallel analysis, segregating populations of cowpea resistant to Macrophomina phaseolina and Thanatephorus cucumeris, based on the evaluation of general (GCA) and specific combining ability (SCA), involved in the genetic control of resistance. For this reason, 19 grouped cowpea genotypes, considering the resistance to these pathogens, were crossed in partial diallel scheme 14 x 5, during 2013 and 2014. The 70 F 2 populations and the 19 parents were evaluated in a greenhouse as the reaction to pathogens, separately. The diallel analysis was performed according to the model of partial diallel proposed by Geraldi and Miranda Filho (1988). The additive effects predominated in the genetic control of the traits severity of charcoal rot (SEV) and area under the disease progress curve (AUDPC) to web blight, enabling the achievement of genetic gain with selection of resistant strains. Analyzing the effects of GCA, the parents BR 14-Mulato, BRS Tumucumaque and BRS Guariba, have a higher concentration of favorable alleles, highlighting, according to the values of SCA, the combinations BR 14-Mulato x MNC02-675F-4-10, BRS Tumucumaque x IT98K-1092-1, BRS Tumucumaque x MNC02-675F-4-10, BRS Tumucumaque x MNC02-675F-9-2, BRS Guariba x IT98K-1092-1, BRS Guariba x MNC02-675F-4-9, and BRS Guariba x MNC02-675F-4-10, as the most promising and indicated to obtain lines resistant to M. phaseolina and T. cucumeris in cowpea, simultaneously.

  20. Antifungal activity of various essential oils against Rhizoctonia solani and Macrophomina phaseolina as major bean pathogens.

    Science.gov (United States)

    Khaledi, N; Taheri, P; Tarighi, S

    2015-03-01

    The main objective of this study was to investigate the effect of various essential oils (EOs) to decrease the activity of cell wall degrading enzymes (CWDEs) produced by fungal phytopathogens, which are associated with disease progress. Also, effect of seed treatment and foliar application of peppermint EO and its main constituent, menthol, on diseases caused by two necrotrophic pathogens on bean was investigated. Antifungal activity of EOs on Rhizoctonia solani and Macrophomina phaseolina, as bean pathogens, was evaluated. The EOs of Mentha piperita, Bunium persicum and Thymus vulgaris revealed the highest antifungal activity against fungi. The EO of M. piperita had the lowest minimum inhibitory concentration (MIC) for R. solani among the three EOs tested. This pathogen did not grow in the presence of M. piperita, B. persicum and T. vulgaris EOs at 850, 1200 and 1100 ppm concentrations, respectively. The B. persicum EO had the lowest MIC for M. phaseolina as this fungus did not grow in the presence of M. piperita, B. persicum and T. vulgaris EOs at concentrations of 975, 950 and 1150 ppm, respectively. Hyphae exposed to EOs showed structural changes. Activities of cellulase and pectinase, as main CWDEs of pathogens, decreased by EOs at low concentration without effect on fungal growth. Seed treatment and foliar application of peppermint EO and/or menthol significantly reduced the development of bean diseases caused by both fungi. Higher capability of menthol than peppermint EO in decreasing diseases on bean was observed. Reducing CDWEs activity is a mechanism of EOs' effect on fungi. Higher antifungal activity of menthol compared to peppermint EO was observed not only in vitro but also in vivo. Effect of EOs on CWDEs involved in pathogenesis is described in this study for the first time. Menthol can be used as a botanical fungicide to control destructive fungal diseases on bean. © 2014 The Society for Applied Microbiology.

  1. Morphological and Pathogenic Variability among Macrophomina phaseolina Isolates Associated with Mungbean (Vigna radiata L. Wilczek from Pakistan

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    Umer Iqbal

    2014-01-01

    Full Text Available Macrophomina phaseolina is a serious pathogen of many crops. In the present studies, 65 isolates of Macrophomina phaseolina from different agroecological regions of Punjab and Khyber Pakhtunkhwa provinces of Pakistan were analyzed for morphological and pathogenic variability. Regardless of their geographic origins, significant differences were detected among 65 isolates in their radial growth, sclerotial size, and weight as well as in pathogenicity. Sixteen isolates were rated as fast growing, 11 as slow growing, and the rest of the isolates as medium growing. Nine isolates were classified as large sized, 26 as small sized, and the remaining 30 isolates as medium sized. Thirty five isolates were ranked as heavy weight, 12 as low weight, and the rest of isolates were grouped as medium weight. Ten fungal isolates appeared to be least virulent, whereas eight isolates of diverse origin proved to be highly virulent against mungbean cultivars. The remaining isolates were regarded as moderately virulent. No relationship was found among the morphological characters and pathogenicity of the isolates. These morphological and pathogenic variations in various isolates of M. phaseolina may be considered important in disease management systems and will be useful in breeding programmes of mungbean cultivars resistant to charcoal rot.

  2. RAPD cluster analysis and chlorate sensitivity of some Indian isolates of Macrophomina phaseolina from sorghum and their relationships with pathogenicity.

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    Das, I K; Fakrudin, B; Arora, D K

    2008-01-01

    Charcoal rot caused by Macrophomina phaseolina is an economically important disease in sorghum grown during the post rainy season in India. Variations in random amplified polymorphic DNA (RAPD) polymorphisms, chlorate sensitivity and pathogenicity were studied among sorghum isolates of M. phaseolina collected from different parts of India. RAPD data based on 14 random primers of Kit A and C (OPA and OPC) on 20 isolates showed a high degree of polymorphism (98.1%) in different isolates. UPGMA dendrogram on RAPD data produced 7 clusters at the level of 37% similarity. Isolates from the same locations showed a tendency to group closer, substantiating closer genetic relatedness. Sorghum infecting Macrophomina isolates showed a mixed response for sensitivity to potassium chlorate (120 mM). Chlorate-resistant isolates were predominant (>65% of the isolates) over sensitive isolates. Chlorate-sensitive isolates were found to be genetically closer among them than the resistant ones. For the first time it was shown that chlorate sensitivity in Macrophomina had some relations with charcoal rot severity in sorghum.

  3. Management of Meloidogyne incognita race 3 and Macrophomina phaseolina by fungus culture filtrates and Bacillus subtilis on chickpea

    OpenAIRE

    Siddiqui, Z.A.; Mahmood, I.

    1995-01-01

    #Bacillus subtilis$ et des filtrats de culture des champignons #Aspergillus niger, Curvularia tuberculata$ et #Penicillium coryophilum$ ont été utilisés, seuls ou en combinaison, comme traitement de semences pour protéger le pois chiche contre une maladie racinaire complexe associant le nématode "Meloidogyne incognita$ race 3 et le champignon #Macrophomina phaseolina$. D'une manière générale, les traitements à l'aide de ces quatre agents, seuls ou en combinaison, accroissent le poids sec et l...

  4. Effect of rotation of cowpea (Vigna unguiculata) with fonio (Digitaria exilis) and millet (Pennisetum glaucum) on Macrophomina phaseolina densities and cowpea yield

    NARCIS (Netherlands)

    Ndiaye, M.; Termorshuizen, A.J.; Bruggen, van A.H.C.

    2008-01-01

    Macrophomina phaseolina, the causal agent of charcoal rot, causes great damage to cowpea in the Sahel. One of the few options to manage the disease is by cropping nonhosts that may reduce the soil inoculum below a damage threshold level. To test this, fonio (Digitaria exilis) and millet (Pennisetum

  5. Pathogenic and Genetic Diversity among Iranian Isolates of Macrophomina phaseolina Diversidad Patogénica y Genética entre Aislamientos Iraníes de Macrophomina phaseolina

    Directory of Open Access Journals (Sweden)

    Siavosh Rayatpanah

    2012-03-01

    Full Text Available Charcoal rot, caused by Macrophomina phaseolina (Tassi Goid., is an economically important disease of oilseed plants in Northern Iran. Seventy isolates of M. phaseolina were obtained from different hosts, including soybean (Glycine max L., and sunflower (Helianthus annuus L. in the northern oilseed planting regions of Iran. RAPD-PCR amplification profiles, by using of six random OPA primers (kit A showed polymorphisms among the isolates. The primer OPA-13 (5'_ CAGCACCCAC_3' amplified the genomic DNA of all isolates of M.phaseolina producing 4-12 bands of sizes between 0.25 and 2.3 kb. Unweighted pair-group method with arithmetic mean (UPGMA analysis classified the isolates into the nine major groups with 64% similarity. Pathogenicity of isolates was evaluated at seedling stage of soybean, sunflower, and maize (Zea mays L. plants under in vitro conditions. None of the isolates were pathogenic on corn, while all of the isolates infected soybean and sunflower seedlings. Isolates were more virulent on soybean than sunflower. The disease index on sunflower and soybean varied between 19-24 and 27-30 respectively. These results indicated a significant pathogenic and genetic variability within the Iranian isolates of M. phaseolina. Cultivation with crop rotation was probably tended to induce less diversity of the pathogen isolates.Pudrición carbonosa, causada por Macrophomina phaseolina (Tassi Goid., es una enfermedad de importancia económica de las plantas de semillas oleaginosas en el norte de Irán. Setenta aislamientos de M. phaseolina se obtuvieron de diferentes hospederos, incluyendo soya (Glycine max L. y girasol (Helianthus annuus L. en las regiones de plantación de semillas oleaginosas del norte de Irán. Perfiles RAPD-PCR de amplificación, utilizando primers aleatorios de seis OPA (kit A mostraron polimorfismos entre los aislamientos. El primer OPA-13 (5'-CAGCACCCAC-3' amplificó el ADN genómico de todos los aislamientos de M. phaseolina

  6. [Biochemical basis of tolerance to osmotic stress in phytopathogenic fungus: The case of Macrophomina phaseolina (Tassi) Goid.

    Science.gov (United States)

    Martínez-Villarreal, Rodolfo; Garza-Romero, Tamar S; Moreno-Medina, Víctor R; Hernández-Delgado, Sanjuana; Mayek-Pérez, Netzahualcoyotl

    Fungus Macrophomina phaseolina (Tassi) Goid. is the causative agent of charcoal rot disease which causes significant yield losses in major crops such as maize, sorghum, soybean and common beans in Mexico. This fungus is a facultative parasite which shows broad ability to adapt itself to stressed environments where water deficits and/or high temperature stresses commonly occur. These environmental conditions are common for most cultivable lands throughout Mexico. Here we describe some basic facts related to the etiology and epidemiology of the fungus as well as to the importance of responses to stressed environments, particularly to water deficits, based on morphology and growth traits, as well as on physiology, biochemistry and pathogenicity of fungus M. phaseolina. To conclude, we show some perspectives related to future research into the genus, which emphasize the increasing need to improve the knowledge based on the application of both traditional and biotechnological tools in order to elucidate the mechanisms of resistance to environmental stress which can be extrapolated to other useful organisms to man. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Genetic Variability of Macrophomina phaseolina Isolates from Dry Beans in Turkey

    OpenAIRE

    Serkan Yeşil; Kubilay Kurtuluş Baştaş

    2016-01-01

    Charcoal rot is a soil and seed borne, economically important fungal disease on dry bean in Turkey. Twenty bean isolates of M. phaseolina collected from different locations in Turkey during 2008 and 2012 years were studied for genetic variability using random amplified polymorphic DNA (RAPD) assay, chlorate sensitivity on medium supplemented with 120mM of potassium, phenotype of colony, and pathogenicity. Isolates were identified as M. phaseolina based on morhological features and PCR assays ...

  8. Efeito de coberturas do solo sobre a sobrevivência de Macrophomina phaseolina no feijão-caupi

    Directory of Open Access Journals (Sweden)

    Cheyla Magdala de Sousa Linhares

    2016-06-01

    Full Text Available RESUMO Com o objetivo de avaliar a sobrevivência de Macrophomina phaseolina em solo submetido a diferentes coberturas, conduziu-se dois experimentos em casa de vegetação, no delineamento inteiramente casualizado, em esquema fatorial 5 x 2, com cinco coberturas (Brachiaria brizantha, Pennisetum glaucum, Crotalaria spectabilis, solo coberto com filme de polietileno e solo sem cobertura e solo esterilizado e não esterilizado. No primeiro experimento, as plantas foram cultivadas em vasos e dessecadas, para posterior plantio do feijão-caupi e no segundo, a semeadura da cultura foi realizada em sucessão ao primeiro cultivo. Nos dois experimentos foram colocadas em cada vaso a 10 cm de profundidade, no dia do plantio da cultura, quatro bolsas de tecido contendo, cada uma, 10 gramas de inóculo de M. phaseolina, das quais, duas foram retiradas aos 30 dias após o plantio e duas no final do ciclo da cultura, para posterior plaqueamento e determinação da sobrevivência. Realizou-se também o monitoramento das temperaturas máximas e mínimas diárias do solo. Os tratamentos com solo coberto com material vegetal apresentaram menor elevação da temperatura em relação ao solo coberto com filme de polietileno e sem cobertura, que elevaram a temperatura em até 5,9 e 3,9 ºC, respectivamente, em relação ao solo coberto com palhada de P. glaucum. O solo coberto com filme de polietileno e sem cobertura apresentaram maiores taxas de sobrevivência de M. phaseolina e o solo coberto com palhada de P. glaucum a menor taxa. Maior sobrevivência foi observada no solo não esterilizado.

  9. Inhibitory Effect of Sambucus ebulus Extracts on Growth of Macrophomina phaseolina and Extraction of their Bioactive

    Directory of Open Access Journals (Sweden)

    Maede Shahiri Tabarestani

    2017-03-01

    Full Text Available Introduction: Macrophomina phaseolina is the causal agent of soybean charcoal rot. This disease is one of the most prevalent and destructive of soybean in the north of Iran. This pathogen has broad host range and invades more than 500 plant species of 75 families, such as Caprifoliaceae. Symptoms on stems appear as silver-gray lesions near the base, which eventually decay the stem. Plants show poor seed fill, premature ripening, and undersized heads. Seed yield and oil content are decreased. Numerous tiny black bodies called sclerotia are formed on the decayed tissues giving the stalks a charred appearance. This fungus exists in the soil as sclerotia, a compact mass of hardened mycelia structures, which can remain dormant for many years. As the causal agent, is a soil-borne pathogen, chemical fungicides are not effective for its control. This matter has led to use a large amount of fungicides that are harmful to human health and lead to environmental pollution. There is not any registered fungicide against the charcoal rot pathogen. Some medicinal plants have a potential for controlling various phytopathogenic fungi due to the variety of compounds. Scientists are trying to achieve some plant-derived compounds for diseases control. Natural plant products are biodegradable, show structural diversity and rarely consist halogenated atoms. These can act directly as pesticides or may supply structure lead to pesticidal discovery. The aim of this study was to investigate chemical composition and antifungal activity of alcoholic and aqueous extracts of Sambucus ebulus for control of M. phaseolina and replace the chemical fungicides. Materials and Methods: The plant leaves were collected during July - August 2014 in Babol (Mazandaran province- Iran and washed thoroughly with tap water and then rinsed with distilled water and shade dried at room temperature. The dried plant material was finely powdered using an electric grinder and used for aqueous and

  10. Green synthesis of protein capped silver nanoparticles from phytopathogenic fungus Macrophomina phaseolina (Tassi) Goid with antimicrobial properties against multidrug-resistant bacteria

    OpenAIRE

    Chowdhury, Supriyo; Basu, Arpita; Kundu, Surekha

    2014-01-01

    In recent years, green synthesis of nanoparticles, i.e., synthesizing nanoparticles using biological sources like bacteria, algae, fungus, or plant extracts have attracted much attention due to its environment-friendly and economic aspects. The present study demonstrates an eco-friendly and low-cost method of biosynthesis of silver nanoparticles using cell-free filtrate of phytopathogenic fungus Macrophomina phaseolina. UV-visible spectrum showed a peak at 450 nm corresponding to the plasmon ...

  11. Biological control of strawberry soil-borne pathogens Macrophomina phaseolina and Fusarium solani, using Trichoderma asperellum and Bacillus spp.

    Directory of Open Access Journals (Sweden)

    Ana María PASTRANA

    2016-05-01

    Full Text Available In south-western Spain, Macrophomina phaseolina and Fusarium solani were found to be associated in strawberry plants with, respectively, charcoal rot, and crown and root rot symptoms. For management of both fungal diseases, the antagonistic effects of two commercial formulations, one based on Trichoderma asperellum T18 strain (Prodigy® and the other on Bacillus megaterium and B. laterosporus (Fusbact®, were evaluated in vitro and under controlled environment and field conditions. Two inoculation methods (root-dipping and soil application and two application times (pre- and post-pathogen inoculation, as preventive and curative treatments, respectively were assessed. Dual plate confrontation experiments demonstrated the antagonistic effects of T. asperellum and Bacillus spp. by inhibiting radial growth of M. phaseolina and F. solani by more than 36%. Preventive application of T. asperellum by root-dipping reduced the incidence of charcoal rot (up to 44% in a growth chamber and up to 65% under field conditions and also reduced disease progression, the percentage of crown necrosis, as well as the level of infection measured as ng of pathogen DNA g-1 plant by quantitative real-time PCR. This treatment was also the most effective for reduction of crown and root rot caused by F. solani (up to 100% in a greenhouse and up to 81% under field conditions. These results were nearly comparable with the control achieved using chemical fungicides. The Bacillus spp.-based formulation was also effective for control of charcoal rot and showed variable results for control of F. solani, depending on the growth conditions.

  12. Genetic Variability of Macrophomina phaseolina Isolates from Dry Beans in Turkey

    Directory of Open Access Journals (Sweden)

    Serkan Yeşil

    2016-04-01

    Full Text Available Charcoal rot is a soil and seed borne, economically important fungal disease on dry bean in Turkey. Twenty bean isolates of M. phaseolina collected from different locations in Turkey during 2008 and 2012 years were studied for genetic variability using random amplified polymorphic DNA (RAPD assay, chlorate sensitivity on medium supplemented with 120mM of potassium, phenotype of colony, and pathogenicity. Isolates were identified as M. phaseolina based on morhological features and PCR assays using species-specific primers (MPKF1and MPKR1. Isolates of M. phaseolina were analysed for their aggressiveness on the susceptible bean cv. Akman 98, by soil inoculation method. Isolates exhibiting a dense chlorate phenotype were chlorate-resistant, while those possessing feathery and restricted chlorate phenotypes were chlorate-sensitive. More than half of the isolates (55% were resistant to chlorate and produced dense phenotype, while 35% isolates showed feathery and two isolates (10% showed restricted growth. DNA from 20 isolates was subjected to genetic diversity analysis by the RAPD method using 14 randomly chosen 10-base random primers, and low genetic diversity (33.3% was observed among the tested isolates.

  13. Practical use of CMC-amended rhizobial inoculant for Mucuna pruriens cultivation to enhance the growth and protection against Macrophomina phaseolina.

    Science.gov (United States)

    Aeron, Abhinav; Khare, Ekta; Kumar Arora, Naveen; Kumar Maheshwari, Dinesh

    2012-01-01

    In many parts of the world Mucuna pruriens is used as an important medicinal, forage and green manure crop. In the present investigation the effect of the addition of CMC in carrier during development of bioformulation on shelflife, plant growth promotive and biocontrol activity against Macrophomina phaseolina was screened taking M. pruriens as a test crop. Ensifer meliloti RMP6(Ery+Kan+) and Bradyrhizobium sp. BMP7(Tet+Kan+) (kanamycin resistance engineered by Tn5 transposon mutagenesis) used in the study showed production of siderophore, IAA, solubilizing phosphate and biocontrol of M. phaseolina. RMP6(Ery+Kan+) also showed ACC deaminase activity. The survival of both the strains in sawdust-based bioformulation was enhanced with an increase in the concentration of CMC from 0 to 1%. At 0% CMC Bradyrhizobium sp. BMP7(Tet+Kan+) showed more increase in nodule number/plant (500.00%) than E. meliloti RMP6(Ery+Kan+) (52.38%), over the control in M. phaseolina-infested soil. There was 185.94% and 59.52% enhancement in nodule number/plant by RMP6(Ery+Kan+) and BMP7(Tet+Kan+) with an increase in the concentration of CMC from 0% to 1% in the bioformulations. However further increase in concentration of CMC did not result in enhancement in survival of either the strains or nodule number/plant.

  14. In vitro growth and cell wall degrading enzyme production by Argentinean isolates of Macrophomina phaseolina, the causative agent of charcoal rot in corn.

    Science.gov (United States)

    Ramos, Araceli M; Gally, Marcela; Szapiro, Gala; Itzcovich, Tatiana; Carabajal, Maira; Levin, Laura

    Macrophomina phaseolina is a polyphagous phytopathogen, causing stalk rot on many commercially important species. Damages caused by this pathogen in soybean and maize crops in Argentina during drought and hot weather have increased due its ability to survive as sclerotia in soil and crop debris under non-till practices. In this work, we explored the in vitro production of plant cell wall-degrading enzymes [pectinases (polygalacturonase and polymethylgalacturonase); cellulases (endoglucanase); hemicellulases (endoxylanase) and the ligninolytic enzyme laccase] by several Argentinean isolates of M. phaseolina, and assessed the pathogenicity of these isolates as a preliminary step to establish the role of these enzymes in M. phaseolina-maize interaction. The isolates were grown in liquid synthetic medium supplemented with glucose, pectin, carboxymethylcellulose or xylan as carbon sources and/or enzyme inducers and glutamic acid as nitrogen source. Pectinases were the first cell wall-degrading enzymes detected and the activities obtained (polygalacturonase activity was between 0.4 and 1.3U/ml and polymethylgalacturonase between 0.15 and 1.3U/ml) were higher than those of cellulases and xylanases, which appeared later and in a lesser magnitude. This sequence would promote initial tissue maceration followed by cell wall degradation. Laccase was detected in all the isolates evaluated (activity was between 36U/l and 63U/l). The aggressiveness of the isolates was tested in maize, sunflower and watermelon seeds, being high on all the plants assayed. This study reports for the first time the potential of different isolates of M. phaseolina to produce plant cell wall-degrading enzymes in submerged fermentation. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Leaf blight of catharanthus roseus (l). g. don caused by macrophomina phaseolina (tassi) goid and its in vitro control through bio-pesticides

    International Nuclear Information System (INIS)

    Mridha, M.A.U.; Rehman, M.M.

    2015-01-01

    Catharanthus roseus (L.).G. Don, a highly valued medicinal plant suffers from a serious disease. A survey on the symptom and severity of the leaf blight of C. roseus was performed in the nurseries of the Institute of Forestry and Environmental Sciences (IFESCU), Bangladesh Council of Industrial Research (BCSIR) and Bangladesh Forest Research Institute (BFRI), Bangladesh. An observation was also made in the avenues and garden of King Saud University (KSU), Kingdom of Saudi Arabia. No disease was recorded in KSU, but severe infections were found in all the locations surveyed in Bangladesh. The highest infection percentage and the highest disease index were found in BCSIR nursery followed by BFRI and the lowest was recorded in IFESCU nursery. Macrophomina phaseolina (Tassi) Goid was isolated and it was proved to be pathogenic. This is the first report of leaf blight of C. roseus caused by M. phaseolina. Azadirachta indica, Ocimum sanctum Vitex negundo, Mucuna pruriens, Calotropis procera, Terminalia arjuna, Allium sativum, Zingiber officinalis and Allium cepa were used as biopesticides. Out of the nine plant species screened, T. arjuna showed the highest (58.37%) inhibition percentage which was followed by A. indica (55.72%) and the lowest (27.4%) inhibition percentage were obtained with V. negundo whereas the rest of the plant extracts showed more or less same inhibitory effect. (author)

  16. A direct observation technique for evaluating sclerotium germination by Macrophomina phaseolina and effects of biocontrol materials on survival of sclerotia in soil.

    Science.gov (United States)

    Pratt, Robert G

    2006-08-01

    Germination of sclerotia of Macrophomina phaseolina was quantified by direct microscopic observation following application of experimental treatments in vitro and incubation of sclerotia in soil. To assay germination, pieces of agar containing sclerotia were macerated in dilute, liquid cornmeal agar on glass slides; thinly spread; and incubated in a saturated atmosphere for 18-22 h. Germinated sclerotia then were identified by morphological features of germ hyphae. Frequencies of germination were similar in three dilute agar media. Germination was not affected by air-drying sclerotia for 2 weeks, but it was significantly reduced after 4 weeks and greatly reduced or eliminated after 6 or 8 weeks. Survival of sclerotia for 14 days in soil was greatest at 50, 75, and 100% moisture-holding capacity, less at 0 and 25%, and least at 125% (flooded soil). Incorporation of ground poultry litter into soil at 5% by weight reduced survival of sclerotia after 13 days, and incorporation of litter at 10% nearly eliminated it. These results indicate that the direct-observation technique may be used to evaluate animal wastes and other agricultural byproducts for biocontrol activity against sclerotia of M. phaseolina in soil.

  17. Genic SNP markers and legume synteny reveal candidate genes underlying QTL for Macrophomina phaseolina resistance and maturity in cowpea [Vigna unguiculata (L Walp.

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    Ehlers Jeffrey D

    2011-01-01

    Full Text Available Abstract Background Macrophomina phaseolina is an emerging and devastating fungal pathogen that causes significant losses in crop production under high temperatures and drought stress. An increasing number of disease incidence reports highlight the wide prevalence of the pathogen around the world and its contribution toward crop yield suppression. In cowpea [Vigna unguiculata (L Walp.], limited sources of low-level host resistance have been identified, the genetic basis of which is unknown. In this study we report on the identification of strong sources of host resistance to M. phaseolina and the genetic mapping of putative resistance loci on a cowpea genetic map comprised of gene-derived single nucleotide polymorphisms (SNPs and amplified fragment length polymorphisms (AFLPs. Results Nine quantitative trait loci (QTLs, accounting for between 6.1 and 40.0% of the phenotypic variance (R2, were identified using plant mortality data taken over three years in field experiments and disease severity scores taken from two greenhouse experiments. Based on annotated genic SNPs as well as synteny with soybean (Glycine max and Medicago truncatula, candidate resistance genes were found within mapped QTL intervals. QTL Mac-2 explained the largest percent R2 and was identified in three field and one greenhouse experiments where the QTL peak co-located with a SNP marker derived from a pectin esterase inhibitor encoding gene. Maturity effects on the expression of resistance were indicated by the co-location of Mac-6 and Mac-7 QTLs with maturity-related senescence QTLs Mat-2 and Mat-1, respectively. Homologs of the ELF4 and FLK flowering genes were found in corresponding syntenic soybean regions. Only three Macrophomina resistance QTLs co-located with delayed drought-induced premature senescence QTLs previously mapped in the same population, suggesting that largely different genetic mechanisms mediate cowpea response to drought stress and Macrophomina infection

  18. Effect of different Gramineae carbon inputs on efficacy of ASD for control of Macrophomina phaseolina in strawberry

    Science.gov (United States)

    Anaerobic soil disinfestation (ASD), using either orchard grass (GR) or wheat shoots (WH) as the carbon input, was examined for the control of M. phaseolina in strawberry. The pathogen was artificially infested at a density of 2.5 sclerotia g-1 soil. Treatments included in the study were ASD with or...

  19. Green synthesis of protein capped silver nanoparticles from phytopathogenic fungus Macrophomina phaseolina (Tassi) Goid with antimicrobial properties against multidrug-resistant bacteria

    Science.gov (United States)

    2014-01-01

    In recent years, green synthesis of nanoparticles, i.e., synthesizing nanoparticles using biological sources like bacteria, algae, fungus, or plant extracts have attracted much attention due to its environment-friendly and economic aspects. The present study demonstrates an eco-friendly and low-cost method of biosynthesis of silver nanoparticles using cell-free filtrate of phytopathogenic fungus Macrophomina phaseolina. UV-visible spectrum showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM) revealed the presence of spherical silver nanoparticles of the size range 5 to 40 nm, most of these being 16 to 20 nm in diameter. X-ray diffraction (XRD) spectrum of the nanoparticles exhibited 2θ values corresponding to silver nanoparticles. These nanoparticles were found to be naturally protein coated. SDS-PAGE analysis showed the presence of an 85-kDa protein band responsible for capping and stabilization of the silver nanoparticles. Antimicrobial activities of the silver nanoparticles against human as well as plant pathogenic multidrug-resistant bacteria were assayed. The particles showed inhibitory effect on the growth kinetics of human and plant bacteria. Furthermore, the genotoxic potential of the silver nanoparticles with increasing concentrations was evaluated by DNA fragmentation studies using plasmid DNA. PMID:25114655

  20. Antagonistic effects of Bacillus subtilis subsp. subtilis and B. amyloliquefaciens against Macrophomina phaseolina: SEM study of fungal changes and UV-MALDI-TOF MS analysis of their bioactive compounds.

    Science.gov (United States)

    Torres, M J; Brandan, C Pérez; Petroselli, G; Erra-Balsells, R; Audisio, M C

    2016-01-01

    The antifungal effect of Bacillus subtilis subsp. subtilis PGPMori7 and Bacillus amyloliquefaciens PGPBacCA1 was evaluated against Macrophomina phaseolina (Tassi) Goid. Cell suspension (CS), cell-free supernatant (CFS) and the lipopeptide fraction (LF) of PGPMori7 and PGPBacCA1 were screened against three different M. phaseolina strains. CS exhibited the highest inhibitory effect (around 50%) when compared to those of CFS and LF, regardless of the fungal strain studied. The synthesis of lipopeptides was studied by UV-MALDI TOF. Chemical analysis of Bacillus metabolite synthesis revealed that surfactin and iturin were mainly produced in liquid medium. Potential fengycin was also co-produced when both Bacillus were cultivated in solid medium. In co-culture assays, the bacterial colony-fungal mycelium interface at the inhibition zone was evaluated by both scanning electron microscopy (SEM) and UV-MALDI TOF, the former to determine the structural changes on M. phaseolina cells and the latter to identify the main bioactive molecules involved in the inhibitory effect. PGPBacCA1 produced surfactin, iturin and fengycin in the inhibition zone while PGPMori7 only produced these metabolites within its colony and not in the narrow inhibition zone. Interestingly, SEM revealed that PGPBacCA1 induced damage in M. phaseolina sclerotia, generating a fungicidal effect as no growth was observed when normal growth conditions were reestablished. In turn, PGPMori7 inhibited the growth of the Macrophomina mycelium without fungal injury, resulting only in a fungistatic activity. From these results, it was determined that the two bacilli significantly inhibited the growth of an important phytopathogenic fungus by at least two different mechanisms: lipopeptide synthesis and competition among microorganisms. Copyright © 2015 Elsevier GmbH. All rights reserved.

  1. Métodos de inoculação de Rhizoctonia bataticola (taub. (Macrophomina phaseolina (tassi goid em sementes de feijão

    Directory of Open Access Journals (Sweden)

    Raimunda Nonata Oliveira da Silva

    2016-11-01

    Full Text Available A utilização de métodos de inoculação constitui uma ferramenta essencial no manejo de doenças, estudo de resistência, seleção e aplicação de produtos. O estudo teve como objetivo avaliar a eficiência de diferentes métodos de inoculação de Rhizoctonia bataticola em sementes de feijão. Os tratamentos constituíram de diferentes métodos de inoculação: suspensão de hifas, contato com restrição hídrica, inoculação do substrato com discos de BDA contendo micélio do fungo e um tratamento controle. Após a inoculação das sementes, foram feitas avaliações de emergência, comprimento de parte aérea, massa seca de parte aérea e incidência de doença na folha e no caule. O delineamento experimental foi inteiramente casualizado, com oito repetições, sendo os dados foram submetidos à análise de variância, sendo as médias comparadas pelo teste a Tukey 5% de probabilidade. O método de inoculação por suspensão de hifas é o mais adequado para inoculação de Rhizoctonia bataticola em sementes de feijão, visto que proporcionou uma maior incidência de plântulas infectadas sem afetar a emergência. Rhizoctonia inoculation methods bataticola (taub. (Phaseolina Macrophomina (tassi goid in bean seeds Abstract: The use of inoculation methods is an essential tool in the management of diseases, study of resistance, selection and application products. The study aimed to evaluate the efficiency of different Rhizoctonia inoculation methods bataticola in bean seeds. The treatments consisted of different methods of inoculation: hyphae suspension, contact with water restriction, inoculation of the substrate with BDA discs containing fungal mycelium and a control treatment. After inoculation of the seeds were made emergency assessments, shoot length, dry weight of shoot and incidence of disease in the leaf and stem. The experimental design was completely randomized with eight repetitions, the data and were subjected to analysis of

  2. Nitric oxide production by necrotrophic pathogen Macrophomina phaseolina and the host plant in charcoal rot disease of jute: complexity of the interplay between necrotroph-host plant interactions.

    Directory of Open Access Journals (Sweden)

    Tuhin Subhra Sarkar

    Full Text Available M. phaseolina, a global devastating necrotrophic fungal pathogen causes charcoal rot disease in more than 500 host plants. With the aim of understanding the plant-necrotrophic pathogen interaction associated with charcoal rot disease of jute, biochemical approach was attempted to study cellular nitric oxide production under diseased condition. This is the first report on M. phaseolina infection in Corchorus capsularis (jute plants which resulted in elevated nitric oxide, reactive nitrogen species and S nitrosothiols production in infected tissues. Time dependent nitric oxide production was also assessed with 4-Amino-5-Methylamino-2',7'-Difluorofluorescein Diacetate using single leaf experiment both in presence of M. phaseolina and xylanases obtained from fungal secretome. Cellular redox status and redox active enzymes were also assessed during plant fungal interaction. Interestingly, M. phaseolina was found to produce nitric oxide which was detected in vitro inside the mycelium and in the surrounding medium. Addition of mammalian nitric oxide synthase inhibitor could block the nitric oxide production in M. phaseolina. Bioinformatics analysis revealed nitric oxide synthase like sequence with conserved amino acid sequences in M. phaseolina genome sequence. In conclusion, the production of nitric oxide and reactive nitrogen species may have important physiological significance in necrotrophic host pathogen interaction.

  3. Evaluación de la susceptibilidad a Macrophomina phaseolina (Tassi Goid en diferentes variedades e híbridos comerciales de sorgo en Sinaloa, México

    Directory of Open Access Journals (Sweden)

    Tomás Moreno Gallegos

    2017-01-01

    Full Text Available El objetivo del presente trabajo fue evaluar la reacción a M. phaseolina de tres variedades experimentales y siete variedades d e polinización libre del INIFAP, así como 14 híbridos comerciales de sorgo, con la finalidad de identificar variedades e híbridos que puedan presentar tolerancia o menor susceptibilidad a esta enfermedad. Los experimentos se establecieron en Culiacán, Sina loa, México, durante los ciclos Primavera - Verano de 2010 y 2011, bajo condiciones de campo en temporal. Se utilizó un diseño de bloques al azar en cada experimento con tres repeticiones y un análisis combinado para los dos ciclos agrícolas. La parcela expe rimental consistió en inocular 10 plantas con mondadientes infectados del hongo. El análisis de varianza detecto diferencias significativas (p<0.05 en longitud de lesión ocasionada por el hongo entre años. En el ciclo 2010, se observó una longitud de lesi ón promedio significativamente mayor (10.10 cm en comparación con el ciclo 2011 (5.79 cm. Los genotipos con menor longitud de lesión en promedio de los dos ambientes fueron: Fortuna y Mazatlán - 16 (3.5 y 4.95 cm, respectivamente . L os genotipos con mayor longitud de lesión fueron Kilate, G - STAR - 7402 y G - STAR - 7205 (13.2, 15.7 y 16.65 cm, respectivamente. No existió correlación entre la longitud de lesión y rendimiento de grano. Las variedades Fortuna y Mazatlán - 16 mostraron menor daño a M. phaseolina , por lo cual se sugieren para siembras de temporal y como progenitores en la formación de híbridos de sorgo tolerantes a esta enfermedad.

  4. Avirulent mutants of Macrophomina phaseolina and Aspergillus ...

    Indian Academy of Sciences (India)

    A human pathogen, Aspergillus fumigatus was also able to infect germinating seeds of P. mungo in the presence of 5 g/ml concentration of phaseolinone. Phaseolinone seemed to facilitate infection by A. fumigatus, which is not normally phytopathogenic, by reducing the immunity of germinating seedlings in a nonspecific ...

  5. Ecology and management of charcoal rot (Macrophomina phaseolina) on cowpea in the Sahel

    NARCIS (Netherlands)

    Ndiaye, M.

    2007-01-01

    Keywords: Senegal/Niger/rotation/millet/isolate characterization/fonio/compost amendment / bioagent/ Clonostachysrosea /solarizationCowpea ( Vignaunguiculata Walp.) is the most important pulse crop in

  6. What regulates crab predation on mangrove propagules?

    Science.gov (United States)

    Van Nedervelde, Fleur; Cannicci, Stefano; Koedam, Nico; Bosire, Jared; Dahdouh-Guebas, Farid

    2015-02-01

    Crabs play a major role in some ecosystems. To increase our knowledge about the factors that influence crab predation on propagules in mangrove forests, we performed experiments in Gazi Bay, Kenya in July 2009. We tested whether: (1) crab density influences propagule predation rate; (2) crab size influences food competition and predation rate; (3) crabs depredate at different rates according to propagule and canopy cover species; (4) vegetation density is correlated with crab density; (5) food preferences of herbivorous crabs are determined by size, shape and nutritional value. We found that (1) propagule predation rate was positively correlated to crab density. (2) Crab competitive abilities were unrelated to their size. (3) Avicennia marina propagules were consumed more quickly than Ceriops tagal except under C. tagal canopies. (4) Crab density was negatively correlated with the density of A. marina trees and pneumatophores. (5) Crabs prefer small items with a lower C:N ratio. Vegetation density influences crab density, and crab density affects propagule availability and hence vegetation recruitment rate. Consequently, the mutual relationships between vegetation and crab populations could be important for forest restoration success and management.

  7. Microbial transformation of sesquitepenoid ketone, (+) Nootkatone by Macrophomia phaseolina

    OpenAIRE

    Vajira P. Bulugahapitiya; Syed Ghulam Musharaff

    2009-01-01

    Microbial transformation is an effective tool for the structural modification of bioactive natural and synthetic compounds leading to synthesis of more potent derivatives. Its application in asymmetric synthesis is increasing due to its versatility and ease. This article presents biotransformation of sesquiterpenoid ketone, (+)-Nootkatone (1) by M. phaseolina, a plant pathogenic fungus. The transformation afforded four main compounds. They were determined to be 1:6 stereoisomeric mixture of 1...

  8. Propagule pressure governs establishment of an invasive herb

    Science.gov (United States)

    Ramula, Satu; Jauni, Miia; van Ooik, Tapio

    2015-10-01

    The success of plant invasions may be limited by the availability of propagules and/or of suitable microsites, with microsite availability being affected by, for example, disturbance and interspecific competition. A mechanistic understanding of the contributions of propagule pressure and microsite limitation to plant invasions is therefore required to minimise future invasions. Here, we investigated the relative roles of propagule pressure, the availability of microsites, and their interaction on the establishment of an invasive herb, Lupinus polyphyllus, in two geographic regions representing different climate and growth conditions in Finland (a more productive southern region and a harsher central region). We carried out a field experiment in 14 L. polyphyllus populations, in which we manipulated both propagule pressure and disturbance. In a complementary greenhouse experiment, we manipulated propagule pressure and interspecific competition. Seedling establishment of L. polyphyllus was higher in the more productive southern region than in the harsher central region. The number of L. polyphyllus seedlings increased with increasing propagule pressure regardless of disturbance or interspecific competition. However, the number of L. polyphyllus seedlings per sown seed (relative establishment) tended to decrease with increasing propagule pressure, indicating that the positive effect of propagule pressure on early invasion is partially counteracted by density-dependent mortality at high seed densities. Our results highlight the dominant role of propagule pressure over disturbance and interspecific competition in the establishment of L. polyphyllus, suggesting that the early stage of invasion is limited by the availability of propagules rather than the availability of suitable microsites.

  9. Relative Efficacy of On-Farm Weeds as Soil-Amendement for Managing Dry Root Rot of Clusterbean in an Arid Environment

    Directory of Open Access Journals (Sweden)

    R. Mawar

    2006-12-01

    Full Text Available The effectiveness of certain on-farm weeds as soil amendments was ascertained against Macrophomina phaseolina, a soil-borne pathogen causing dry root rot of crops grown under rainfed conditions in arid regions. Population changes in M. phaseolina were determined in soils amended separately with residues (1%, w:w of Aerva persica, Celosia argentea, Corchorus depressus, Euphorbia hirta, Heliotropium subulatum and Polycarpaea corymbosa, for a period of 90 days. Significant reductions by 90.4–100% in the population of M. phaseolina were achieved with all the weed residues except P. corymbosa. Celosia and Euphorbia residues completely eradicated viable propagules of M. phaseolina. A strong increase (44–61% in the population of antagonistic actinomycetes was also found in soil amended with Corchorus and Euphorbia. In field tests, soil amended (50 g m2 with Euphorbia, Aerva and Celosia residues significantly reduced dry root rot incidence on clusterbean and also reduced M. phaseolina propagules in the soil. However, dry root rot incidence in Polycarpaea-amended soil (5.8–24.6% was not significantly different from that in non-amended soil (4.3–25.3% in both years of the experiment. P. corymbosa also increased the number of propagules of M. phaseolina in the soil. The results demonstrate that dry root rot of rainfed-cultivated annual crops in arid land can be managed with certain weeds as a soil amendment.

  10. The role of wind in hydrochorous mangrove propagule dispersal

    Directory of Open Access Journals (Sweden)

    T. Van der Stocken

    2013-06-01

    Full Text Available Although wind has been recognized to be an important factor in the dispersal of hydrochorous mangrove propagules, and hence in the quantification of (metapopulation dynamics, the species-specific sensitivity to wind effects has not been studied. We combined observations from a controlled experiment (flume tank and in situ experiments to understand wind and water current contributions to dispersal potential as well as to estimate real dispersal ranges due to immediate response to tidal currents (two outgoing tides. This was done for 4 species with propagules differing in morphological and buoyancy properties (i.e. Rhizophora mucronata, Ceriops tagal, Heritiera littoralis and Xylocarpus granatum. The flume experiments revealed that the influence of wind depends on the density of a propagule (and hence its buoyancy characteristics and that typical morphological characteristics of the dispersal unit are additionally important. H. littoralis propagules were influenced most, because on the one hand their low density (613.58 g L−1; n =10 enables them to float on top of the water surface, and on the other hand their "sailboat-like" structure provides a relatively large surface area. The X. granatum fruits appeared to be the least influenced by ambient wind conditions, explained by the smooth surface and spherical shape of which, because of the fruit's high density (890.05 g L−1; n = 1, only a small part sticks above the water surface. Although the seeds of X. granatum are of a similar size class than H. littoralis propagules, they are (like the X. granatum fruits largely submerged due to their high density (870.66 g L−1; n = 8, hence catching less wind than H. littoralis propagules. The influence of wind on the dispersal of the horizontally floating C. tagal and R. mucronata dispersal units was strong, comparable to that of H. littoralis propagules. A differential effect of wind was found within elongated propagules, which directly follows from

  11. Release of Streptomyces albus propagules from contaminated surfaces

    International Nuclear Information System (INIS)

    Gorny, R.L.; Mainelis, Gediminas; Grinshpun, Sergey A.; Willeke, Klaus; Dutkiewicz, Jacek; Reponen, Tiina

    2003-01-01

    The release of Streptomyces albus propagules from contaminated agar an ceiling tile surfaces was studied under controlled environmental condition in a newly developed aerosolization chamber. The experiments revealed tha both spores and cell fragments can be simultaneously released from the colonized surface by relatively gentle air currents of 0.3 m s -1 . A 100x increase of the air velocity can result in a 50-fold increase in the number of released propagules. The aerosolization rate depends strongly on the typ and roughness of the contaminated surface. Up to 90% of available actinomycete propagules can become airborne during the first 10 min of th release process. Application of vibration to the surface did not reveal an influence on the aerosolization process of S. albus propagules under th tested conditions. This study has shown that propagules in the fine particle size range can be released in large amounts from contaminated surfaces Measurement of the number of S. albus fragments in the vicinity of contaminated area, as an alternative to conventional air or surface sampling appears to be a promising approach for quantitative exposure assessment

  12. Microbial transformation of sesquitepenoid ketone, (+ Nootkatone by Macrophomia phaseolina

    Directory of Open Access Journals (Sweden)

    Vajira P. Bulugahapitiya

    2009-09-01

    Full Text Available Microbial transformation is an effective tool for the structural modification of bioactive natural and synthetic compounds leading to synthesis of more potent derivatives. Its application in asymmetric synthesis is increasing due to its versatility and ease. This article presents biotransformation of sesquiterpenoid ketone, (+-Nootkatone (1 by M. phaseolina, a plant pathogenic fungus. The transformation afforded four main compounds. They were determined to be 1:6 stereoisomeric mixture of 11,12-dihydroxy- 11,12-dihydronootkatone (2, 3, 13-hydroxynootkaone (4 and 12-hydroxy-11,12- dihydronootkatone (5 with the help of EI-MS, HR-FAB-MS(pos, HR-FAB-MS (neg, 1H-NMR, 13CNMR, COSY-450, NOESY, HMBC, HMQC spectral analyses. The compound 4 was firstchandana- amarasingha-samayawardana-avifauna-Bundala-1.1-28.07 identified as Nootkatone metabolites in this study. Further, the parental compound (1 and the transformed products 4 and 5 were found to be present significant antiprotozoal activity.

  13. The role of wind in hydrochorous mangrove propagule dispersal

    NARCIS (Netherlands)

    Van der Stocken, T.; De Ryck, D.J.R.; Balke, T.; Bouma, T.J.; Dahdouh-Guebas, F.; Koedam, N.

    2013-01-01

    Although wind has been recognized to be an important factor in the dispersal of hydrochorous mangrove propagules, and hence in the quantification of (meta)population dynamics, the species-specific sensitivity to wind effects has not been studied. We combined observations from a controlled experiment

  14. Connectivity and propagule sources composition drive ditch plant metacommunity structure

    Science.gov (United States)

    Favre-Bac, Lisa; Ernoult, Aude; Mony, Cendrine; Rantier, Yann; Nabucet, Jean; Burel, Françoise

    2014-11-01

    The fragmentation of agricultural landscapes has a major impact on biodiversity. In addition to habitat loss, dispersal limitation increasingly appears as a significant driver of biodiversity decline. Landscape linear elements, like ditches, may reduce the negative impacts of fragmentation by enhancing connectivity for many organisms, in addition to providing refuge habitats. To characterize these effects, we investigated the respective roles of propagule source composition and connectivity at the landscape scale on hydrochorous and non-hydrochorous ditch bank plant metacommunities. Twenty-seven square sites (0.5 km2 each) were selected in an agricultural lowland of northern France. At each site, plant communities were sampled on nine ditch banks (totaling 243 ditches). Variables characterizing propagule sources composition and connectivity were calculated for landscape mosaic and ditch network models. The landscape mosaic influenced only non-hydrochorous species, while the ditch network impacted both hydrochorous and non-hydrochorous species. Non-hydrochorous metacommunities were dependent on a large set of land-use elements, either within the landscape mosaic or adjacent to the ditch network, whereas hydrochorous plant metacommunities were only impacted by the presence of ditches adjacent to crops and roads. Ditch network connectivity also influenced both hydrochorous and non-hydrochorous ditch bank plant metacommunity structure, suggesting that beyond favoring hydrochory, ditches may also enhance plant dispersal by acting on other dispersal vectors. Increasing propagule sources heterogeneity and connectivity appeared to decrease within-metacommunity similarity within landscapes. Altogether, our results suggest that the ditch network's composition and configuration impacts plant metacommunity structure by affecting propagule dispersal possibilities, with contrasted consequences depending on species' dispersal vectors.

  15. Modelling drivers of mangrove propagule dispersal and restoration of abandoned shrimp farms

    Directory of Open Access Journals (Sweden)

    D. Di Nitto

    2013-07-01

    Full Text Available Propagule dispersal of four mangrove species Rhizophora mucronata, R. apiculata, Ceriops tagal and Avicennia officinalis in the Pambala–Chilaw Lagoon Complex (Sri Lanka was studied by combining a hydrodynamic model with species-specific knowledge on propagule dispersal behaviour. Propagule transport was simulated using a finite-volume advection-diffusion model to investigate the effect of dispersal vectors (tidal flow, freshwater discharge and wind, trapping agents (retention by vegetation and seed characteristics (buoyancy on propagule dispersal patterns. Sensitivity analysis showed that smaller propagules, like the oval-shaped propagules of Avicennia officinalis, dispersed over larger distances and were most sensitive to changing values of retention by mangrove vegetation compared to larger, torpedo-shaped propagules of Rhizophora spp. and C. tagal. Directional propagule dispersal in this semi-enclosed lagoon with a small tidal range was strongly concentrated towards the edges of the lagoon and channels. Short distance dispersal appeared to be the main dispersal strategy for all four studied species, with most of the propagules being retained within the vegetation. Only a small proportion (max. 5% of propagules left the lagoon through a channel connecting the lagoon with the open sea. Wind significantly influenced dispersal distance and direction once propagules entered the lagoon or adjacent channels. Implications of these findings for mangrove restoration were tested by simulating partial removal in the model of dikes around abandoned shrimp ponds to restore tidal hydrology and facilitate natural recolonisation by mangroves. The specific location of dike removal, (with respect to the vicinity of mangroves and independently suitable hydrodynamic flows, was found to significantly affect the resultant quantities and species of inflowing propagules and hence the potential effectiveness of natural regeneration. These results demonstrate the

  16. Airstream Fractionation of Vesicular-Arbuscular Mycorrhizal Fungi: Concentration and Enumeration of Propagules

    OpenAIRE

    Tommerup, Inez C.

    1982-01-01

    Spores and fragments of vesicular-arbuscular mycorrhizal fungi in dry soils were concentrated up to 100-fold when the soils were partitioned by fluidization and elutriation with a series of upward airstreams at progressively increasing velocities. The propagules were transported with the finer soil particles according to their equivalent spherical diameters. The system was used to predict the transport of propagules by wind. Concentrated propagules were rapidly separated from the soil particl...

  17. Pemangsaan Propagul Mangrove Rhizophora sp. Sebagai Bukti Teori Dominance-Predation (Predation of Mangrove Propagule, Rhizophora sp. as Evidence of Dominance-Predation Theory

    Directory of Open Access Journals (Sweden)

    Rudhi Pribadi

    2014-06-01

    Propagule predation on mangrove in some extent reduced its viability to grow into seedling. The predation could happened before (pre-dispersal or after (post-dispersal the propagule drop from the tree.The reasearch was conducted in Pasar Banggi, Rembang District, Central Java. The aim was to investigate the predation rate of Rhizophora mucronata Lamk., R. stylosa Griff. and R. apiculata Blume propagules pre-dispersal and post-dispersal. Firstly, preface experiment for find domination spesies in the location, Second, with applied descriptive-based survey sampling and field experiment methods. Than all propagules of five replication trees were harvested and checked for its condition on pre-dispersal step. The third, with post-dispersal study there were twenty propagules from each spesies and tied them with used nylon string and placed on the forest floor for 2 until 18 days and checked its condition every 2 days after placement. This study is also set for tested the Smith’s theory on propagule predation related to tree domination. Rhizophora stylosa propagule was  most predated before they fall (mean 61,06%, range 45,40-76,05%, followed by R. apiculata (mean 58,18%, range 47,41-68% and the lowest isR. mucronata with mean 11,88% (range 7,06-15,71%. After 18 days of experiment in the field R. stylosa propagule in R. stylosa–dominated area was the lowest predated (mean 46,67% compared to propagule in the area dominated by R. apiculata (63,33% and also in R. mucronata area (83,33 Predated R. mucronata propagule is the highest in the R. mucronata dominated area (mean 95% compared with R. apiculata dominated area (mean 55% and also in R. stylosa dominated area (45%. Pradated of R. apiculata propagule is the lowest in the domination area of R. apiculata (50% compared with R. stylosa area domination with (mean 70% also R. mucronata (73,33%. The result showed that the theory of dominance-predation can be proved only for R. stylosa and R. apiculata spesies, but not for R

  18. Propagule pressure determines recruitment from a commercial shipping pier.

    Science.gov (United States)

    Hedge, Luke H; Johnston, Emma L

    2012-01-01

    Artificial structures associated with shipping and boating activities provide habitats for a diverse suite of non-indigenous marine species. Little is known about the proportion of invader success in nearby waters that is attributable to these structures. Areas close to piles, wharves and piers are likely to be exposed to increasing levels of propagule pressure, enhancing the recruitment of non-indigenous species. Recruitment of non-indigenous and native marine biofouling taxa were evaluated at different distances from a large commercial shipping pier. Since artificial structures also represent a desirable habitat for fish, how predation on marine invertebrates influences the establishment of non-indigenous and native species was also evaluated. The colonisation of several non-indigenous marine species declined rapidly with distance from the structure. Little evidence was found to suggest that predators have much influence on the colonisation success of marine sessile invertebrate species, non-indigenous or otherwise. It is suggested that propagule pressure, not predation, more strongly predicts establishment success in these biofouling assemblages.

  19. Vegetative Propagule Pressure and Water Depth Affect Biomass and Evenness of Submerged Macrophyte Communities.

    Science.gov (United States)

    Li, Hong-Li; Wang, Yong-Yang; Zhang, Qian; Wang, Pu; Zhang, Ming-Xiang; Yu, Fei-Hai

    2015-01-01

    Vegetative propagule pressure may affect the establishment and structure of aquatic plant communities that are commonly dominated by plants capable of clonal growth. We experimentally constructed aquatic communities consisting of four submerged macrophytes (Hydrilla verticillata, Ceratophyllum demersum, Elodea nuttallii and Myriophyllum spicatum) with three levels of vegetative propagule pressure (4, 8 and 16 shoot fragments for communities in each pot) and two levels of water depth (30 cm and 70 cm). Increasing vegetative propagule pressure and decreasing water level significantly increased the growth of the submerged macrophyte communities, suggesting that propagule pressure and water depth should be considered when utilizing vegetative propagules to re-establish submerged macrophyte communities in degraded aquatic ecosystems. However, increasing vegetative propagule pressure and decreasing water level significantly decreased evenness of the submerged macrophyte communities because they markedly increased the dominance of H. verticillata and E. nuttallii, but had little impact on that of C. demersum and M. spicatum. Thus, effects of vegetative propagule pressure and water depth are species-specific and increasing vegetative propagule pressure under lower water level can facilitate the establishment success of submerged macrophyte communities.

  20. Vegetative Propagule Pressure and Water Depth Affect Biomass and Evenness of Submerged Macrophyte Communities.

    Directory of Open Access Journals (Sweden)

    Hong-Li Li

    Full Text Available Vegetative propagule pressure may affect the establishment and structure of aquatic plant communities that are commonly dominated by plants capable of clonal growth. We experimentally constructed aquatic communities consisting of four submerged macrophytes (Hydrilla verticillata, Ceratophyllum demersum, Elodea nuttallii and Myriophyllum spicatum with three levels of vegetative propagule pressure (4, 8 and 16 shoot fragments for communities in each pot and two levels of water depth (30 cm and 70 cm. Increasing vegetative propagule pressure and decreasing water level significantly increased the growth of the submerged macrophyte communities, suggesting that propagule pressure and water depth should be considered when utilizing vegetative propagules to re-establish submerged macrophyte communities in degraded aquatic ecosystems. However, increasing vegetative propagule pressure and decreasing water level significantly decreased evenness of the submerged macrophyte communities because they markedly increased the dominance of H. verticillata and E. nuttallii, but had little impact on that of C. demersum and M. spicatum. Thus, effects of vegetative propagule pressure and water depth are species-specific and increasing vegetative propagule pressure under lower water level can facilitate the establishment success of submerged macrophyte communities.

  1. Potential role of propagule banks in the development of aquatic vegetation in backwaters along navigation canals

    NARCIS (Netherlands)

    Boedeltje, G; Bakker, JP; ter Heerdt, GNJ

    The diversity and abundance of plant species in propagule banks of backwaters along two navigation canals in The Netherlands were studied in order to assess the relationship with the standing vegetation and the potential role of propagule banks in the establishment of (submerged) aquatic vegetation.

  2. Bycatch, bait, anglers, and roads: quantifying vector activity and propagule introduction risk across lake ecosystems.

    Science.gov (United States)

    Drake, D Andrew R; Mandrak, Nicholas E

    2014-06-01

    Long implicated in the invasion process, live-bait anglers are highly mobile species vectors with frequent overland transport of fishes. To test hypotheses about the role of anglers in propagule transport, we developed a social-ecological model quantifying the opportunity for species transport beyond the invaded range resulting from bycatch during commercial bait operations, incidental transport, and release to lake ecosystems by anglers. We combined a gravity model with a stochastic, agent-based simulation, representing a 1-yr iteration of live-bait angling and the dynamics of propagule transport at fine spatiotemporal scales (i.e., probability of introducing n propagules per lake per year). A baseline scenario involving round goby (Neogobius melanostomus) indicated that most angling trips were benign; irrespective of lake visitation, anglers failed to purchase and transport propagules (benign trips, median probability P = 0.99912). However, given the large number of probability trials (4.2 million live-bait angling events per year), even the rarest sequence of events (uptake, movement, and deposition of propagules) is anticipated to occur. Risky trips (modal P = 0.00088 trips per year; approximately 1 in 1136) were sufficient to introduce a substantial number of propagules (modal values, Poisson model = 3715 propagules among 1288 lakes per year; zero-inflated negative binomial model = 6722 propagules among 1292 lakes per year). Two patterns of lake-specific introduction risk emerged. Large lakes supporting substantial angling activity experienced propagule pressure likely to surpass demographic barriers to establishment (top 2.5% of lakes with modal outcomes of five to 76 propagules per year; 303 high-risk lakes with three or more propagules, per year). Small or remote lakes were less likely to receive propagules; however, most risk distributions were leptokurtic with a long right tail, indicating the rare occurrence of high propagule loads to most waterbodies

  3. Photosynthetic planulae and planktonic hydroids: contrasting strategies of propagule survival

    Directory of Open Access Journals (Sweden)

    Patrizia Pagliara

    2000-12-01

    Full Text Available Settlement delays can be important to prevent propagule waste when proper settling substrates are not immediately available. Under laboratory conditions, the planulae of Clytia viridicans underwent two alternative developmental patterns. Some settled on the bottom, forming a hydranth-gonotheca complex that produced up to four medusae and later either degenerated or gave rise to a hydroid colony. Other planulae settled right below the air-water interface, forming floating colonies that eventually fell to the bottom and settled. Halecium nanum released planulae with a rich population of symbiotic zooxanthellae that survived into a rearing jar for three months. After a long period of apparent quiescence (possibly fuelled by photosynthetic activities of zooxanthellae the planulae produced new colonies. Both photosynthetic planulae and settlement at the interface air-water allow a delay in the passage from a planktonic to a fully functional benthic life.

  4. Saltmarsh boundary modulates dispersal of mangrove propagules: implications for mangrove migration with sea-level rise.

    Directory of Open Access Journals (Sweden)

    Jennifer M Peterson

    Full Text Available Few studies have empirically examined the suite of mechanisms that underlie the distributional shifts displayed by organisms in response to changing climatic condition. Mangrove forests are expected to move inland as sea-level rises, encroaching on saltmarsh plants inhabiting higher elevations. Mangrove propagules are transported by tidal waters and propagule dispersal is likely modified upon encountering the mangrove-saltmarsh ecotone, the implications of which are poorly known. Here, using an experimental approach, we record landward and seaward dispersal and subsequent establishment of mangrove propagules that encounter biotic boundaries composed of two types of saltmarsh taxa: succulents and grasses. Our findings revealed that propagules emplaced within saltmarsh vegetation immediately landward of the extant mangrove fringe boundary frequently dispersed in the seaward direction. However, propagules moved seaward less frequently and over shorter distances upon encountering boundaries composed of saltmarsh grasses versus succulents. We uniquely confirmed that the small subset of propagules dispersing landward displayed proportionately higher establishment success than those transported seaward. Although impacts of ecotones on plant dispersal have rarely been investigated in situ, our experimental results indicate that the interplay between tidal transport and physical attributes of saltmarsh vegetation influence boundary permeability to propagules, thereby directing the initial phase of shifting mangrove distributions. The incorporation of tidal inundation information and detailed data on landscape features, such as the structure of saltmarsh vegetation at mangrove boundaries, should improve the accuracy of models that are being developed to forecast mangrove distributional shifts in response to sea-level rise.

  5. Saltmarsh boundary modulates dispersal of mangrove propagules: implications for mangrove migration with sea-level rise.

    Science.gov (United States)

    Peterson, Jennifer M; Bell, Susan S

    2015-01-01

    Few studies have empirically examined the suite of mechanisms that underlie the distributional shifts displayed by organisms in response to changing climatic condition. Mangrove forests are expected to move inland as sea-level rises, encroaching on saltmarsh plants inhabiting higher elevations. Mangrove propagules are transported by tidal waters and propagule dispersal is likely modified upon encountering the mangrove-saltmarsh ecotone, the implications of which are poorly known. Here, using an experimental approach, we record landward and seaward dispersal and subsequent establishment of mangrove propagules that encounter biotic boundaries composed of two types of saltmarsh taxa: succulents and grasses. Our findings revealed that propagules emplaced within saltmarsh vegetation immediately landward of the extant mangrove fringe boundary frequently dispersed in the seaward direction. However, propagules moved seaward less frequently and over shorter distances upon encountering boundaries composed of saltmarsh grasses versus succulents. We uniquely confirmed that the small subset of propagules dispersing landward displayed proportionately higher establishment success than those transported seaward. Although impacts of ecotones on plant dispersal have rarely been investigated in situ, our experimental results indicate that the interplay between tidal transport and physical attributes of saltmarsh vegetation influence boundary permeability to propagules, thereby directing the initial phase of shifting mangrove distributions. The incorporation of tidal inundation information and detailed data on landscape features, such as the structure of saltmarsh vegetation at mangrove boundaries, should improve the accuracy of models that are being developed to forecast mangrove distributional shifts in response to sea-level rise.

  6. Soil propagule banks of ectomycorrhizal fungi share many common species along an elevation gradient.

    Science.gov (United States)

    Miyamoto, Yumiko; Nara, Kazuhide

    2016-04-01

    We conducted bioassay experiments to investigate the soil propagule banks of ectomycorrhizal (EM) fungi in old-growth forests along an elevation gradient and compared the elevation pattern with the composition of EM fungi on existing roots in the field. In total, 150 soil cores were collected from three forests on Mt. Ishizuchi, western Japan, and subjected to bioassays using Pinus densiflora and Betula maximowicziana. Using molecular analyses, we recorded 23 EM fungal species in the assayed propagule banks. Eight species (34.8 %) were shared across the three sites, which ranged from a warm-temperate evergreen mixed forest to a subalpine conifer forest. The elevation pattern of the assayed propagule banks differed dramatically from that of EM fungi on existing roots along the same gradient, where only a small proportion of EM fungal species (3.5 %) were shared across sites. The EM fungal species found in the assayed propagule banks included many pioneer fungal species and composition differed significantly from that on existing roots. Furthermore, only 4 of 23 species were shared between the two host species, indicating a strong effect of bioassay host identity in determining the propagule banks of EM fungi. These results imply that the assayed propagule bank is less affected by climate compared to EM fungal communities on existing roots. The dominance of disturbance-dependent fungal species in the assayed propagule banks may result in higher ecosystem resilience to disturbance even in old-growth temperate forests.

  7. [Soil propagule bank of ectomycorrhizal fungi in natural forest of Pinus bungeana].

    Science.gov (United States)

    Zhao, Nan Xing; Han, Qi Sheng; Huang, Jian

    2017-12-01

    To conserve and restore the forest of Pinu bungeana, we investigated the soil propagule bank of ectomycorrhizal (ECM) fungi in a severely disturbed natural forest of P. bungeana in Shaanxi Province, China. We used a seedling-bioassay method to bait the ECM fungal propagules in the soils collected from the forest site. ECM was identified by combining morph typing with ITS-PCR-sequencing. We obtained 73 unique sequences from the ECM associated with P. bungeana seedlings, and assigned them into 12 ECM fungal OTUs at the threshold of 97% based on the sequence similarity. Rarefaction curve displayed almost all ECM fungi in the propagule bank were detected. The most frequent OTU (80%) showed poor similarity (75%) with existing sequences in the online database, which suggested it might be a new species. Cenococcum geophilum, Tomentella sp., Tuber sp. were common species in the propagule bank. Although C. geophilum and Tomentella sp. were frequently detected in other soil propagule banks of pine forest, the most frequent OTU was not assigned to known genus or family, which indicated the host-specif of ECM propagule banks associa-ted with P. bungeana. This result confirmed the importance of the special ECM propagule banks associated with P. bungeana for natural forest restoration.

  8. Invasion of nitrite oxidizer dominated communities: interactions between propagule pressure and community composition

    DEFF Research Database (Denmark)

    Kinnunen, Marta; Dechesne, Arnaud; Albrechtsen, Hans-Jørgen

    consider a broader community ecology framework. For example, the effect of propagule pressure, often studied in macro-ecology, has rarely been examined for microbial communities. Also, the interactions between processes governing community assembly and propagule pressure on invasion success have never been...... by nitrite oxidizer strain (Candidatus Nitrotoga sp. HW29) at 3 different propagule pressures. The reactors were then operated another 2 weeks before analyzing community composition by targeted qPCRs and 16S rRNA gene amplicon analysis. We successfully assembled resident communities with different ratios...

  9. The risk of establishment of aquatic invasive species: joining invasibility and propagule pressure.

    Science.gov (United States)

    Leung, Brian; Mandrak, Nicholas E

    2007-10-22

    Invasive species are increasingly becoming a policy priority. This has spurred researchers and managers to try to estimate the risk of invasion. Conceptually, invasions are dependent both on the receiving environment (invasibility) and on the ability to reach these new areas (propagule pressure). However, analyses of risk typically examine only one or the other. Here, we develop and apply a joint model of invasion risk that simultaneously incorporates invasibility and propagule pressure. We present arguments that the behaviour of these two elements of risk differs substantially--propagule pressure is a function of time, whereas invasibility is not--and therefore have different management implications. Further, we use the well-studied zebra mussel (Dreissena polymorpha) to contrast predictions made using the joint model to those made by separate invasibility and propagule pressure models. We show that predictions of invasion progress as well as of the long-term invasion pattern are strongly affected by using a joint model.

  10. Airstream fractionation of vesicular-arbuscular mycorrhizal fungi: concentration and enumeration of propagules.

    Science.gov (United States)

    Tommerup, I C

    1982-09-01

    Spores and fragments of vesicular-arbuscular mycorrhizal fungi in dry soils were concentrated up to 100-fold when the soils were partitioned by fluidization and elutriation with a series of upward airstreams at progressively increasing velocities. The propagules were transported with the finer soil particles according to their equivalent spherical diameters. The system was used to predict the transport of propagules by wind. Concentrated propagules were rapidly separated from the soil particles in each soil fraction by an aqueous flotation method. The technique is proposed as a quantitative method for estimating the numbers of spores and fragments of mycorrhizae. The scheme includes a viability test that was used to differentiate between potentially infective propagules and those that were either dormant or incapable of regrowth.

  11. CAPACIDAD ANTAGONISTA DE HONGOS CELULOLÍTICOS FRENTE A Fusarium sp. Y Macrophomina sp.

    Directory of Open Access Journals (Sweden)

    Néstor Leopoldo Tarazona Meza

    2014-12-01

    Full Text Available El objetivo de esta investigación fue evaluar la capacidad antagónica de ocho hongos celulolíticos nativos frente a los hongos fitopatógenos Fusarium sp. y Macrophomina sp. En primera instancia se determinó la cepa promisoria del hongo celulolítico, para lo cual, en caja Petri se colocó un disco de agar de 4 mm de diámetro con micelio de una cepa antagonista y en el extremo opuesto, a una distancia de cinco centímetros aproximadamente, otro disco de 4 mm con micelio de un patógeno. La capacidad antagónica se determinó por el grado de micoparasitismo y la competencia por nutrientes y espacios, registrando el porcentaje de inhibición del crecimiento radial. Con la cepa del hongo celulolítico que tuvo el mejor comportamiento antagonista se realizó un cocultivo independiente con cada patógeno, aquí se evalúo las UFC, crecidas en medio PDA. También se inoculó junto a las cepas fitopatógenas en plantas de pimiento para conocer el nivel de antagonismo en macetas. En la evaluación cualitativa, la cepa A.O-5 mostró una invasión y esporulación total en la superficie en ambos patógenos; mientras que en el cocultivo inhibe el crecimiento de los patógenos a las 96 h. Igualmente demostró su acción antagonista frente a Fusarium y Macrophomina en las plántulas de pimiento. Por lo encontrado, se estima que la cepa A.O-5 es un potencial agente antagonista de los fitopatógenos evaluados.

  12. Landscape characteristics of Rhizophora mangle forests and propagule deposition in coastal environments of Florida (USA)

    Science.gov (United States)

    Sengupta, R.; Middleton, B.; Yan, C.; Zuro, M.; Hartman, H.

    2005-01-01

    Field dispersal studies are seldom conducted at regional scales even though reliable information on mid-range dispersal distance is essential for models of colonization. The purpose of this study was to examine the potential distance of dispersal of Rhizophora mangle propagules by comparing deposition density with landscape characteristics of mangrove forests. Propagule density was estimated at various distances to mangrove sources (R. mangle) on beaches in southwestern Florida in both high-and low-energy environments, either facing open gulf waters vs. sheltered, respectively. Remote sensing and Geographic Information Systems were used to identify source forests and to determine their landscape characteristics (forest size and distance to deposition area) for the regression analyses. Our results indicated that increasing density of propagules stranded on beaches was related negatively to the distance of the deposition sites from the nearest stands of R. mangle and that deposition was greatly diminished 2 km or more from the source. Measures of fragmentation such as the area of the R. mangle forests were related to propagule deposition but only in low-energy environments. Our results suggest that geographic models involving the colonization of coastal mangrove systems should include dispersal dynamics at mid-range scales, i.e., for our purposes here, beyond the local scale of the forest and up to 5 km distant. Studies of mangrove propagule deposition at various spatial scales are key to understanding regeneration limitations in natural gaps and restoration areas. Therefore, our study of mid-range propagule dispersal has broad application to plant ecology, restoration, and modeling. ?? Springer 2005.

  13. Assessing Dispersal Patterns of Fish Propagules from an Effective Mediterranean Marine Protected Area

    Science.gov (United States)

    Di Franco, Antonio; Coppini, Giovanni; Pujolar, José Martin; De Leo, Giulio A.; Gatto, Marino; Lyubartsev, Vladyslav; Melià, Paco; Zane, Lorenzo; Guidetti, Paolo

    2012-01-01

    Successfully enforced marine protected areas (MPAs) have been widely demonstrated to allow, within their boundaries, the recovery of exploited species and beyond their boundaries, the spillover of juvenile and adult fish. Little evidence is available about the so-called ‘recruitment subsidy’, the augmented production of propagules (i.e. eggs and larvae) due to the increased abundance of large-sized spawners hosted within effective MPAs. Once emitted, propagules can be locally retained and/or exported elsewhere. Patterns of propagule retention and/or export from MPAs have been little investigated, especially in the Mediterranean. This study investigated the potential for propagule production and retention/export from a Mediterranean MPA (Torre Guaceto, SW Adriatic Sea) using the white sea bream, Diplodus sargus sargus, as a model species. A multidisciplinary approach was used combining 1) spatial distribution patterns of individuals (post-settlers and adults) assessed through visual census within Torre Guaceto MPA and in northern and southern unprotected areas, 2) Lagrangian simulations of dispersal based on an oceanographic model of the region and data on early life-history traits of the species (spawning date, pelagic larval duration) and 3) a preliminary genetic study using microsatellite loci. Results show that the MPA hosts higher densities of larger-sized spawners than outside areas, potentially guaranteeing higher propagule production. Model simulations and field observation suggest that larval retention within and long-distance dispersal across MPA boundaries allow the replenishment of the MPA and of exploited populations up to 100 km down-current (southward) from the MPA. This pattern partially agrees with the high genetic homogeneity found in the entire study area (no differences in genetic composition and diversity indices), suggesting a high gene flow. By contributing to a better understanding of propagule dispersal patterns, these findings provide

  14. Optimal methods for fitting probability distributions to propagule retention time in studies of zoochorous dispersal.

    Science.gov (United States)

    Viana, Duarte S; Santamaría, Luis; Figuerola, Jordi

    2016-02-01

    Propagule retention time is a key factor in determining propagule dispersal distance and the shape of "seed shadows". Propagules dispersed by animal vectors are either ingested and retained in the gut until defecation or attached externally to the body until detachment. Retention time is a continuous variable, but it is commonly measured at discrete time points, according to pre-established sampling time-intervals. Although parametric continuous distributions have been widely fitted to these interval-censored data, the performance of different fitting methods has not been evaluated. To investigate the performance of five different fitting methods, we fitted parametric probability distributions to typical discretized retention-time data with known distribution using as data-points either the lower, mid or upper bounds of sampling intervals, as well as the cumulative distribution of observed values (using either maximum likelihood or non-linear least squares for parameter estimation); then compared the estimated and original distributions to assess the accuracy of each method. We also assessed the robustness of these methods to variations in the sampling procedure (sample size and length of sampling time-intervals). Fittings to the cumulative distribution performed better for all types of parametric distributions (lognormal, gamma and Weibull distributions) and were more robust to variations in sample size and sampling time-intervals. These estimated distributions had negligible deviations of up to 0.045 in cumulative probability of retention times (according to the Kolmogorov-Smirnov statistic) in relation to original distributions from which propagule retention time was simulated, supporting the overall accuracy of this fitting method. In contrast, fitting the sampling-interval bounds resulted in greater deviations that ranged from 0.058 to 0.273 in cumulative probability of retention times, which may introduce considerable biases in parameter estimates. We

  15. Contributions of seed bank and vegetative propagules to vegetation composition on prairie dog colonies in western South Dakota

    Science.gov (United States)

    Emily R. Helms; Lan Xu; Jack L. Butler

    2012-01-01

    Characterizing the contributions of the seed bank and vegetative propagules will enhance our understanding of community resiliency associated with prairie dog disturbances. Our objective was to determine the effects of ecological condition (EC) and distance from burrows on the soil seed bank and vegetative propagules. Based on species composition of the extant...

  16. Aliens in Antarctica: Assessing transfer of plant propagules by human visitors to reduce invasion risk

    NARCIS (Netherlands)

    Huiskes, A.H.L.; Gremmen, N.J.M.; Bergstrom, D.M.; Frenot, Y.; Hughes, K.A.; Imura, S.; Kiefer, K.; Lebouvier, M.; Lee, J.E.; Tsujimoto, M.; Ware, C.; Van de Vijver, B.; Chown, S.L.

    2014-01-01

    Despite considerable research on biological invasions, key areas remain poorly explored, especially ways to reduce unintentional propagule transfer. The Antarctic represents a microcosm of the situation, with the numbers of established non-native species growing. Information to help reduce potential

  17. Morphology of seeds and seedlings of four species of Vigna Savi (Leguminosae, Phaseolinae

    Directory of Open Access Journals (Sweden)

    Fabiana Soledad Ojeda

    2013-09-01

    Full Text Available Four neotropical species of Vigna Savi (Leguminosae, Phaseolinae have potential value as forage crops or ornamentals and could be cultivated in tropical or subtropical areas, even on floodplains. In order to obtain useful data for their culture and taxonomy, the seed morphology, germination pattern (hypogeal or epigeal and seedling development were studied. The studied species belong to different sections of the genus: V. adenantha (G.F.W. Meyer Maréchal, Mascherpa & Stainier (Sect. Leptospron; V. candida (Vell. Maréchal, Mascherpa & Stainier (Sect. Sigmoidotropis; V. caracalla (L. Verdc. (Sect. Caracallae and V. luteola (Jacq. Benth. (Sect. Vigna. The seeds were collected during fieldwork conducted in northwestern and northeastern Argentina. The qualitative and quantitative characters of the seeds were registered, after which they were sown. The development of the emerged seedlings was followed, first in a greenhouse and thereafter in open field. We recorded the type of germination, the thigmotropic movements of the hypocotyl and of the stem, seedling architecture and plant longevity. These traits allowed us to differentiate the species and construct an identification key that could be useful for agronomic or floricultural purposes. The data obtained partially support the current taxonomic treatment of the genus.

  18. Propagule pressure, habitat conditions and clonal integration influence the establishment and growth of an invasive clonal plant, Alternanthera philoxeroides

    Directory of Open Access Journals (Sweden)

    Wen-Hua eYou

    2016-05-01

    Full Text Available Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules may affect the establishment, growth and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments or low (one fragment propagule pressure was established either in bare soil (open habitat or dense native vegetation of Jussiaea repens (vegetative habitat, with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions.

  19. Propagule pressure, genetic structure, and geographic origins of Chondrilla juncea (Asteraceae): An apomictic invader on three continents

    Science.gov (United States)

    Assessing the propagule pressure and geographic origins of invasive populations using molecular markers provides insights into the invasion process. Rush skeletonweed (Chondrilla juncea) is an apomictic perennial plant that is invasive in Australia, Argentina, Canada and the USA. Invasive biotypes...

  20. A review of the genus Bulbothrix Hale: the species with medullary salazinic acid lacking vegetative propagules

    Directory of Open Access Journals (Sweden)

    Michel Benatti

    2012-10-01

    Full Text Available Descriptions are presented for the seven known Bulbothrix (Parmeliaceae, Lichenized Fungi species with salazinic acid in the medulla and without vegetative propagules. Bulbothrix continua, previously considered as a synonym of B. hypocraea, is recognized as independent species. The current delimitations are confirmed for B. enormis, B. hypocraea, B. meizospora, B. linteolocarpa, B. sensibilis, and B. setschwanensis. New characteriscs and range extensions are provided.

  1. Sewage input reduces the consumption of Rhizophora mangle propagules by crabs in a subtropical mangrove system.

    Science.gov (United States)

    Boehm, Frederike Ricarda; Sandrini-Neto, Leonardo; Moens, Tom; da Cunha Lana, Paulo

    2016-12-01

    Mangrove forests are highly productive and play a major role in global carbon cycling. Their carbon accumulation can be influenced through the consumption of nutrient-poor leaves and propagules by herbivore crabs. Anthropogenic nutrient input from sewage contamination is widespread in these often naturally nutrient-limited ecosystems. We hypothesised that sewage-mediated nutrient input to mangrove stands of Paranaguá Bay (southern Brazil), would alter the nutrient sources available for crabs, e.g. through microphytobenthos increase, and that this would reflect in their feeding behaviour. We predicted that propagules of Rhizophora mangle in contaminated stands would experience lower grazing pressure from their two main local consumers (Ucides cordatus and Goniopsis cruentata). We compared herbivory rates on R. mangle propagules in sewage contaminated and uncontaminated mangrove stands. We found that herbivory rates were significantly lower in contaminated than uncontaminated forests, but this pattern could not be clearly attributed to increased nutrient availability. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Wind pollination and propagule formation in Rhizophora mangle L. (Rhizophoraceae: resource or pollination limitation?

    Directory of Open Access Journals (Sweden)

    TARCILA L. NADIA

    2014-03-01

    Full Text Available Rhizophora mangle is considered as a self-compatible mangrove, and is pollinated by wind and insects. However, there is no information about fruit production by autogamy and agamospermy and on the foraging behavior of its flower visitors. Hence, the present study analyzed the pollination and reproductive systems of R. mangle in a mangrove community in northern Pernambuco, Brazil. Floral morphology, sequence of anthesis, and behavior of flower visitors were described; the proportion of flowers that resulted in mature propagules was also recorded. Autogamy, agamospermy, and wind pollination tests were performed, and a new anemophily index is proposed. The flowers of R. mangle are hermaphrodite, protandric, and have high P/O rate. Flies were observed on flowers only during the male phase, probably feeding on mites that consume pollen. Rhizophora mangle is not agamospermic and its fruit production rate by spontaneous self-pollination is low (2.56% compared to wind pollination (19.44%. The anemophily index was high 0.98, and thus it was considered as a good indicator. Only 13.79% of the flowers formed mature propagules. The early stages of fruit development are the most critical and susceptible to predation. Rhizophora mangle is, therefore, exclusively anemophilous in the study area and the propagule dispersal seems to be limited by herbivory.

  3. Arbuscular mycorrhizal propagules in soils from a tropical forest and an abandoned cornfield in Quintana Roo, Mexico: visual comparison of most-probable-number estimates.

    Science.gov (United States)

    Ramos-Zapata, José A; Guadarrama, Patricia; Navarro-Alberto, Jorge; Orellana, Roger

    2011-02-01

    The present study was aimed at comparing the number of arbuscular mycorrhizal fungi (AMF) propagules found in soil from a mature tropical forest and that found in an abandoned cornfield in Noh-Bec Quintana Roo, Mexico, during three seasons. Agricultural practices can dramatically reduce the availability and viability of AMF propagules, and in this way delay the regeneration of tropical forests in abandoned agricultural areas. In addition, rainfall seasonality, which characterizes deciduous tropical forests, may strongly influence AMF propagules density. To compare AMF propagule numbers between sites and seasons (summer rainy, winter rainy and dry season), a "most probable number" (MPN) bioassay was conducted under greenhouse conditions employing Sorgum vulgare L. as host plant. Results showed an average value of 3.5 ± 0.41 propagules in 50 ml of soil for the mature forest while the abandoned cornfield had 15.4 ± 5.03 propagules in 50 ml of soil. Likelihood analysis showed no statistical differences in MPN of propagules between seasons within each site, or between sites, except for the summer rainy season for which soil from the abandoned cornfield had eight times as many propagules compared to soil from the mature forest site for this season. Propagules of arbuscular mycorrhizal fungi remained viable throughout the sampling seasons at both sites. Abandoned areas resulting from traditional slash and burn agriculture practices involving maize did not show a lower number of AMF propagules, which should allow the establishment of mycotrophic plants thus maintaining the AMF inoculum potential in these soils.

  4. Consumption of coral propagules after mass spawning enhances larval quality of damselfish through maternal effects.

    Science.gov (United States)

    McCormick, Mark I

    2003-06-01

    The synchronized spawning of corals in many parts of the Indo-Pacific represents a huge injection of biological material into the waters around reefs. Much of this material is consumed by fishes and filter-feeding invertebrates in the 5 or so days following spawning. The present study is the first to document the effect of the consumption of coral propagules on a population of facultatively planktivorous fish and the transference of physiological condition across generations. The study compares two populations of the damselfish Pomacentrus amboinensis that fed to differing degrees on coral propagules for 5 days after the annual mass spawning of corals at Lizard Island, Great Barrier Reef, Australia. Wind blew coral slicks over the outer lagoon to the inner lagoon some 1.5 km away. While coral propagules were abundant in the water column in the windward location, they were scarce by the time the water mass reached the inner lagoon. Behavioral observations 2-5 days after coral spawning showed that a significantly higher proportion of P. amboinensis was feeding on coral propagules in the windward location than in the inner lagoon location. Windward location females consumed coral propagules almost exclusively and had fuller guts than females from the inner lagoonal location. Five days after the mass coral spawning, windward location females had a higher condition factor and a larger liver mass relative to body mass compared to females within the inner lagoon or females from both locations 2 months later. Fish eggs laid by the windward location females soon after coral spawning yielded larvae that had 25% larger yolk sacs and 100% larger oil globules than did larvae produced from the females from the inner lagoon location, or larvae produced at either location prior to or well after coral spawning in 2 previous years. Larger yolk sacs and oil globules have been shown to have direct survival benefits in the transition from endogenous to exogenous feeding. A feeding

  5. The role of propagule pressure, genetic diversity and microsite availability for Senecio vernalis invasion.

    Directory of Open Access Journals (Sweden)

    Alexandra Erfmeier

    Full Text Available Genetic diversity is supposed to support the colonization success of expanding species, in particular in situations where microsite availability is constrained. Addressing the role of genetic diversity in plant invasion experimentally requires its manipulation independent of propagule pressure. To assess the relative importance of these components for the invasion of Senecio vernalis, we created propagule mixtures of four levels of genotype diversity by combining seeds across remote populations, across proximate populations, within single populations and within seed families. In a first container experiment with constant Festuca rupicola density as matrix, genotype diversity was crossed with three levels of seed density. In a second experiment, we tested for effects of establishment limitation and genotype diversity by manipulating Festuca densities. Increasing genetic diversity had no effects on abundance and biomass of S. vernalis but positively affected the proportion of large individuals to small individuals. Mixtures composed from proximate populations had a significantly higher proportion of large individuals than mixtures composed from within seed families only. High propagule pressure increased emergence and establishment of S. vernalis but had no effect on individual growth performance. Establishment was favoured in containers with Festuca, but performance of surviving seedlings was higher in open soil treatments. For S. vernalis invasion, we found a shift in driving factors from density dependence to effects of genetic diversity across life stages. While initial abundance was mostly linked to the amount of seed input, genetic diversity, in contrast, affected later stages of colonization probably via sampling effects and seemed to contribute to filtering the genotypes that finally grew up. In consequence, when disentangling the mechanistic relationships of genetic diversity, seed density and microsite limitation in colonization of

  6. The role of propagule pressure, genetic diversity and microsite availability for Senecio vernalis invasion.

    Science.gov (United States)

    Erfmeier, Alexandra; Hantsch, Lydia; Bruelheide, Helge

    2013-01-01

    Genetic diversity is supposed to support the colonization success of expanding species, in particular in situations where microsite availability is constrained. Addressing the role of genetic diversity in plant invasion experimentally requires its manipulation independent of propagule pressure. To assess the relative importance of these components for the invasion of Senecio vernalis, we created propagule mixtures of four levels of genotype diversity by combining seeds across remote populations, across proximate populations, within single populations and within seed families. In a first container experiment with constant Festuca rupicola density as matrix, genotype diversity was crossed with three levels of seed density. In a second experiment, we tested for effects of establishment limitation and genotype diversity by manipulating Festuca densities. Increasing genetic diversity had no effects on abundance and biomass of S. vernalis but positively affected the proportion of large individuals to small individuals. Mixtures composed from proximate populations had a significantly higher proportion of large individuals than mixtures composed from within seed families only. High propagule pressure increased emergence and establishment of S. vernalis but had no effect on individual growth performance. Establishment was favoured in containers with Festuca, but performance of surviving seedlings was higher in open soil treatments. For S. vernalis invasion, we found a shift in driving factors from density dependence to effects of genetic diversity across life stages. While initial abundance was mostly linked to the amount of seed input, genetic diversity, in contrast, affected later stages of colonization probably via sampling effects and seemed to contribute to filtering the genotypes that finally grew up. In consequence, when disentangling the mechanistic relationships of genetic diversity, seed density and microsite limitation in colonization of invasive plants, a clear

  7. Influence of the size of garlic propagules on radiosensitivity of clones

    International Nuclear Information System (INIS)

    Perez Talavera, S.; Acevedo, A.M.; Perez, A.

    1989-01-01

    The influence of the size of garlic propagules selected to be irradiated on the results of radiosensitivity was studied so as to determine the useful radiation doses for improvement. This was done using radio inhibition of the plant height index as criteria and the mahalanobis distance stadigrapher calculated among defined groups for the behaviour of cloves in reference to six radiation doses. Significative differences were found among dose-effect curves obtained when using big cloves and small cloves, in five garlic clones, as well as different behaviours of clone radiosensitivity when it was investigated using the two proposed variants

  8. Factors influencing survival of vesicular-arbuscular mycorrhiza propagules during topsoil storage

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.M.; Carnes, B.A.; Moorman, T.B.

    1985-01-01

    The survival dynamics of vesicular-arbuscular mycorrhizal fungi were determined, (using a bioassay procedure) for soils stored from 0.5 to 6.0 years in topsoil stockpiles associated with a coal surface-mine in the western United States. Propagule mortality could best be related to in situ soil moisture potential using a piecewise regression model (R/sup 2/ = 0.57; P less than or equal to 0.001) with the breaking point occurring at -2 MPa. The addition of length of storage time was found to contribute significantly to the accuracy of the model (R/sup 2/ = 0.70; P less than or equal to 0.001). In addition, the piece-wise nature of the data suggested two separate populations of VAM fungi - those propagules found in soils with moisture potentials less than -2 MPa and those occurring in soils with moisture potentials greater than -2 MPa. Soil moisture and length of storage time had differing effects on each of these populations. When water potential was less than -2 MPa, moisture was an important predictor of inoculum (P < 0.001), while length of storage had little predictive capability (P = 0.17). However, when water potentials were greater than -2 MPa, the predictive importance of soil moisture (P = 0.86) and length of storage (P = 0.04) were reversed. The significance of these findings to topsoil replacement and subsequent plant community development are discussed. 28 references, 2 figures, 2 tables.

  9. Comparative performance of two air samplers for monitoring airborne fungal propagules

    Directory of Open Access Journals (Sweden)

    L.G.F. Távora

    2003-05-01

    Full Text Available Many studies have attempted to evaluate the importance of airborne fungi in the development of invasive fungal infection, especially for immunocompromised hosts. Several kinds of instruments are available to quantitate fungal propagule levels in air. We compared the performance of the most frequently used air sampler, the Andersen sampler with six stages, with a portable one, the Reuter centrifugal sampler (RCS. A total of 84 samples were analyzed, 42 with each sampler. Twenty-eight different fungal genera were identified in samples analyzed with the Andersen instrument. In samples obtained with the RCS only seven different fungal genera were identified. The three most frequently isolated genera in samples analyzed with both devices were Penicillium, Aspergillus and Cladophialophora. In areas supplied with a high efficiency particulate air filter, fungal spore levels were usually lower when compared to areas without these filters. There was a significant correlation between total fungal propagule measurements taken with both devices on each sampling occasion (Pearson coefficient = 0.50. However, the Andersen device recovered a broader spectrum of fungi. We conclude that the RCS can be used for quantitative estimates of airborne microbiological concentrations. For qualitative studies, however, this device cannot be recommended.

  10. Effect of 2,4diacetylphloroglucinol of Pythium: cellular responses and variation in sensitivity among propagules and species

    NARCIS (Netherlands)

    Souza, J.T.; Arnould, C.; Deulvot, C.; Lemanceau, P.; Gianinazzi-Pearson, V.; Raaijmakers, J.M.

    2003-01-01

    The antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) plays an important role in the suppression of plant pathogens by several strains of Pseudomonas spp. Based on the results of this study, there is variation within and among Pythium spp. to 2,4-DAPG. Also, various propagules of Pythium ultimum var.

  11. Propagules of arbuscular mycorrhizal fungi in a secondary dry forest of Oaxaca, Mexico

    Directory of Open Access Journals (Sweden)

    Patricia Guadarrama

    2008-03-01

    Full Text Available Plant cover loss due to changes in land use promotes a decrease in spore diversity of arbuscular mycorrhizal fungi (AMF, viable mycelium and, therefore, in AMF colonization, this has an influence in community diversity and, as a consequence, in its recovery. To evaluate different AMF propagules, nine plots in a tropical dry forest with secondary vegetation were selected: 0, 1, 7, 10, 14, 18, 22, 25, and 27 years after abandonment in Nizanda, Oaxaca, Mexico. The secondary vegetation with different stages of development is a consequence of slash and burn agriculture, and posterior abandonment. Soil samples (six per plot were collected and percentage of AMF field colonization, extrarradical mycelium, viable spore density, infectivity and most probable number (MPN of AMF propagules were quantified through a bioassay. Means for field colonization ranged between 40 % and 70 %, mean of total mycelium length was 15.7 ± 1.88 mg-1 dry soil, with significant differences between plots; however, more than 40 % of extracted mycelium was not viable, between 60 and 456 spores in 100 g of dry soil were recorded, but more than 64 % showed some kind of damage. Infectivity values fluctuated between 20 % and 50 %, while MPN showed a mean value of 85.42 ± 44.17 propagules (100 g dry soil. We conclude that secondary communities generated by elimination of vegetation with agricultural purposes in a dry forest in Nizanda do not show elimination of propagules, probably as a consequence of the low input agriculture practices in this area, which may encourage natural regeneration. Rev. Biol. Trop. 56 (1: 269-277. Epub 2008 March 31.La vegetación secundaria con diferentes grados de desarrollo es consecuencia de prácticas agrícolas de roza-tumba-quema y su posterior abandono. La remoción de la vegetación por cambios de uso de suelo promueve una disminución en la diversidad de esporas, micelio viable y por lo tanto de la colonización de los hongos micorriz

  12. Management of foliar and soilborne pathogens of cowpea (Vigna ...

    African Journals Online (AJOL)

    SAM

    2014-04-23

    Apr 23, 2014 ... spores and sclerotial production of Macrophomina phaseolina (Tassi) Goid, Colletotrichum destructivum O gara .... out using the same method but was concentrated to about 2 ml with ..... Plant clinic handbook IMI. Technical.

  13. Effects of phosphate solubilizing microorganisms and Rhizobium sp ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-04

    Aug 4, 2009 ... position due to its nutritive values (17-23% protein) in large vegetarian .... Macrophomina phaseolina was isolated from infected chickpea root samples ... inoculated into each pot around the pea seedling. Another PSM,.

  14. Assessing the effects of habitat patches ensuring propagule supply and different costs inclusion in marine spatial planning through multivariate analyses.

    Science.gov (United States)

    Appolloni, L; Sandulli, R; Vetrano, G; Russo, G F

    2018-05-15

    Marine Protected Areas are considered key tools for conservation of coastal ecosystems. However, many reserves are characterized by several problems mainly related to inadequate zonings that often do not protect high biodiversity and propagule supply areas precluding, at the same time, economic important zones for local interests. The Gulf of Naples is here employed as a study area to assess the effects of inclusion of different conservation features and costs in reserve design process. In particular eight scenarios are developed using graph theory to identify propagule source patches and fishing and exploitation activities as costs-in-use for local population. Scenarios elaborated by MARXAN, software commonly used for marine conservation planning, are compared using multivariate analyses (MDS, PERMANOVA and PERMDISP) in order to assess input data having greatest effects on protected areas selection. MARXAN is heuristic software able to give a number of different correct results, all of them near to the best solution. Its outputs show that the most important areas to be protected, in order to ensure long-term habitat life and adequate propagule supply, are mainly located around the Gulf islands. In addition through statistical analyses it allowed us to prove that different choices on conservation features lead to statistically different scenarios. The presence of propagule supply patches forces MARXAN to select almost the same areas to protect decreasingly different MARXAN results and, thus, choices for reserves area selection. The multivariate analyses applied here to marine spatial planning proved to be very helpful allowing to identify i) how different scenario input data affect MARXAN and ii) what features have to be taken into account in study areas characterized by peculiar biological and economic interests. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Propagule pressure, genetic structure, and geographic origins of Chondrilla juncea (Asteraceae): an apomictic invader on three continents.

    Science.gov (United States)

    Gaskin, John F; Schwarzländer, Mark; Kinter, C Lynn; Smith, James F; Novak, Stephen J

    2013-09-01

    Assessing propagule pressure and geographic origins of invasive species provides insight into the invasion process. Rush skeletonweed (Chondrilla juncea; Asteraceae) is an apomictic, perennial plant that is invasive in Australia, South America (Argentina), and North America (Canada and the United States). This study comprehensively compares propagule pressure and geographic structure of genotypes to improve our understanding of a clonal invasion and enhance management strategies. • We analyzed 1056 native range plants from Eurasia and 1156 plants from three invaded continents using amplified fragment length polymorphism (AFLP) techniques. We used measures of diversity (Simpson's D) and evenness (E), analysis of molecular variance, and Mantel tests to compare invasions, and genotype similarity to determine origins of invasive genotypes. • We found 682 unique genotypes in the native range, but only 13 in the invaded regions. Each invaded region contained distinct AFLP genotypes, suggesting independent introduction events, probably with different geographic origins. Relatively low propagule pressure was associated with each introduction around the globe, but levels of among-population variation differed. We found exact AFLP genotype matches between the native and invaded ranges for five of the 13 invasive genotypes. • Invasion dynamics can vary across invaded ranges within a species. Intensive sampling for molecular analyses can provide insight for understanding intraspecific invasion dynamics, which can hold significance for the management of plant species, especially by finding origins and distributions of invasive genotypes for classical biological control efforts.

  16. Predicting how altering propagule pressure changes establishment rates of biological invaders across species pools.

    Science.gov (United States)

    Brockerhoff, Eckehard G; Kimberley, Mark; Liebhold, Andrew M; Haack, Robert A; Cavey, Joseph F

    2014-03-01

    Biological invasions resulting from international trade can cause major environmental and economic impacts. Propagule pressure is perhaps the most important factor influencing establishment, although actual arrival rates of species are rarely recorded. Furthermore, the pool of potential invaders includes many species that vary in their arrival rate and establishment potential. Therefore, we stress that it is essential to consider the size and composition of species pools arriving from source regions when estimating probabilities of establishment and effects of pathway infestation rates. To address this, we developed a novel framework and modeling approach to enable prediction of future establishments in relation to changes in arrival rate across entire species pools. We utilized 13 828 border interception records from the United States and New Zealand for 444 true bark beetle (Scolytinae) and longhorned beetle (Cerambycidae) species detected between 1949 and 2008 as proxies for arrival rates to model the relationship between arrival and establishment rates. Nonlinearity in this relationship implies that measures intended to reduce the unintended transport of potential invaders (such as phytosanitary treatments) must be highly effective in order to substantially reduce the rate of future invasions, particularly if trade volumes continue to increase.

  17. Drifting propagules and receding swamps: genetic footprints of mangrove recolonization and dispersal along tropical coasts.

    Science.gov (United States)

    Nettel, Alejandro; Dodd, Richard S

    2007-04-01

    Two issues that have captured the attention of tropical plant evolutionary biologists in recent years are the relative role of long distance dispersal (LDD) over vicariance in determining plant distributions and debate about the extent that Quaternary climatic changes affected tropical species. Propagules of some mangrove species are assumed to be capable of LDD due to their ability to float and survive for long periods of time in salt water. Mangrove species responded to glaciations with a contraction of their range. Thus, widespread mangrove species are an ideal system to study LDD and recolonization in the tropics. We present phylogenetic and phylogeographic analyses based on internal transcribed spacers region (ITS) sequences, chloroplast DNA (cpDNA), and amplified fragment length polymorphisms (AFLPs) of genomic DNA that demonstrate recent LDD across the Atlantic, rejecting the hypothesis of vicariance for the widespread distribution of the black mangrove (Avicennia germinans). Northern latitude populations likely became extinct during the late Quaternary due to frosts and aridification; these locations were recolonized afterward from southern populations. In some low latitude regions populations went extinct or were drastically reduced during the Quaternary because of lack of suitable habitat as sea levels changed. Our analyses show that low latitude Pacific populations of A. germinans harbor more diversity and reveal deeper divergence than Atlantic populations. Implications for our understanding of phylogeography of tropical species are discussed.

  18. Propagule pressure and climate contribute to the displacement of Linepithema humile by Pachycondyla chinensis.

    Directory of Open Access Journals (Sweden)

    Eleanor Spicer Rice

    Full Text Available Identifying mechanisms governing the establishment and spread of invasive species is a fundamental challenge in invasion biology. Because species invasions are frequently observed only after the species presents an environmental threat, research identifying the contributing agents to dispersal and subsequent spread are confined to retrograde observations. Here, we use a combination of seasonal surveys and experimental approaches to test the relative importance of behavioral and abiotic factors in determining the local co-occurrence of two invasive ant species, the established Argentine ant (Linepithema humile Mayr and the newly invasive Asian needle ant (Pachycondyla chinensis Emery. We show that the broader climatic envelope of P. chinensis enables it to establish earlier in the year than L. humile. We also demonstrate that increased P. chinensis propagule pressure during periods of L. humile scarcity contributes to successful P. chinensis early season establishment. Furthermore, we show that, although L. humile is the numerically superior and behaviorally dominant species at baits, P. chinensis is currently displacing L. humile across the invaded landscape. By identifying the features promoting the displacement of one invasive ant by another we can better understand both early determinants in the invasion process and factors limiting colony expansion and survival.

  19. Quantifying potential propagule pressure of aquatic invasive species from the commercial shipping industry in Canada.

    Science.gov (United States)

    Lo, Veronica B; Levings, Colin D; Chan, Kai M A

    2012-02-01

    We quantify and compare different measures of potential propagule pressure (PPP) of aquatic invasive species (AIS) from commercial vessels in Canada. We used ship arrivals and ballast water discharge volumes as proxies for PPP from ballast water organisms, and wetted surface area (WSA) as a proxy for hull fouling PPP, to determine their relative contributions to total PPP. For three regions studied, PPP proxies correlated significantly across ports and some vessel categories. Relative contributions of ship arrivals, ballast discharge, and WSAs to PPP, evidenced by non-significant correlations across these measures, varied across regions, ports, vessel types, and seasons. Flow-through (dominant on east and west coasts) and empty-refill (in Great Lakes-St. Lawrence region) were the major ballast water exchange methods employed by the vessels surveyed. These methods have different biological efficacy for AIS removal, influencing PPP. Our study illustrates benefits and limitations of using different PPP proxies to estimate invasion risk. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Biochemical response and host-pathogen relation of stalk rot fungi ...

    African Journals Online (AJOL)

    Stalk rot is a destructive disease in maize caused by Fusarium and Macrophomina species. A study was carried out to understand the mode of infection, host biochemical response and comparison of inoculation techniques in Fusarium verticillioides and Macrophomina phaseolina in maize. In seed inoculation experiment, ...

  1. Use of Lagrangian simulations to hindcast the geographical position of propagule release zones in a Mediterranean coastal fish.

    Science.gov (United States)

    Calò, Antonio; Lett, Christophe; Mourre, Baptiste; Pérez-Ruzafa, Ángel; García-Charton, José Antonio

    2018-03-01

    The study of organism dispersal is fundamental for elucidating patterns of connectivity between populations, thus crucial for the design of effective protection and management strategies. This is especially challenging in the case of coastal fish, for which information on egg release zones (i.e. spawning grounds) is often lacking. Here we assessed the putative location of egg release zones of the saddled sea bream (Oblada melanura) along the south-eastern coast of Spain in 2013. To this aim, we hindcasted propagule (egg and larva) dispersal using Lagrangian simulations, fed with species-specific information on early life history traits (ELTs), with two approaches: 1) back-tracking and 2) comparing settler distribution obtained from simulations to the analogous distribution resulting from otolith chemical analysis. Simulations were also used to assess which factors contributed the most to dispersal distances. Back-tracking simulations indicated that both the northern sector of the Murcia region and some traits of the North-African coast were hydrodynamically suitable to generate and drive the supply of larvae recorded along the coast of Murcia in 2013. With the second approach, based on the correlation between simulation outputs and field results (otolith chemical analysis), we found that the oceanographic characteristics of the study area could have determined the pattern of settler distribution recorded with otolith analysis in 2013 and inferred the geographical position of main O. melanura spawning grounds along the coast. Dispersal distance was found to be significantly affected by the geographical position of propagule release zones. The combination of methods used was the first attempt to assess the geographical position of propagule release zones in the Mediterranean Sea for O. melanura, and can represent a valuable approach for elucidating dispersal and connectivity patterns in other coastal species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Quantitative, molecular and growth analyses of Ulva microscopic propagules in the coastal sediment of Jiangsu province where green tides initially occurred.

    Science.gov (United States)

    Liu, Feng; Pang, Shao Jun; Zhao, Xiao Bo; Hu, Chuan Ming

    2012-03-01

    From 2007 to 2011, large-scale green tides formed by unattached filamentous alga, Ulva prolifera in Ulva linza-procera-prolifera complex, have initially occurred in Jiangsu coasts of China. The real niche or the substrate(s) on which U. prolifera attaches before it starts to float is still under debate. However, great numbers of Ulva propagules would be supposed to exist in the microscopic, overwintering stage for the next spring's bloom in coastal environments. This study was designed to confirm the above prediction and investigate abundance, species composition and growth characteristics of Ulva propagules in the sediments. Quantification result showed that Ulva propagules widely distributed in the sediments and the abundance of these isolates did not change much over a 3-month testing period at low temperature in darkness. Molecular data based on three DNA markers revealed that four Ulva species existed in the sediments, among which green-tide forming alga, U. prolifera, was included. Elevated levels of temperature, irradiance as well as nutrients in seawater greatly facilitated recovery and growth of propagules. Results of this investigation indicated the possibility of microscopic propagules turning directly into floating biomass in season when temperature, irradiance and nutrients together meet the required levels in questioned coastal water area. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Invasibility of a nutrient-poor pasture through resident and non-resident herbs is controlled by litter, gap size and propagule pressure.

    Directory of Open Access Journals (Sweden)

    R Lutz Eckstein

    Full Text Available Since inference concerning the relative effects of propagule pressure, biotic interactions, site conditions and species traits on the invasibility of plant communities is limited, we carried out a field experiment to study the role of these factors for absolute and relative seedling emergence in three resident and three non-resident confamilial herb species on a nutrient-poor temperate pasture. We set up a factorial field experiment with two levels each of the factors litter cover (0 and 400 g m(-2, gap size (0.01 and 0.1 m(2 and propagule pressure (5 and 50 seeds and documented soil temperature, soil water content and relative light availability. Recruitment was recorded in spring and autumn 2010 and in spring 2011 to cover initial seedling emergence, establishment after summer drought and final establishment after the first winter. Litter alleviated temperature and moisture conditions and had positive effects on proportional and absolute seedling emergence during all phases of recruitment. Large gaps presented competition-free space with high light availability but showed higher temperature amplitudes and lower soil moisture. Proportional and absolute seedling recruitment was significantly higher in large than in small gaps. In contrast, propagule pressure facilitated absolute seedling emergence but had no effects on proportional emergence or the chance for successful colonisation. Despite significantly higher initial seedling emergence of resident than non-resident species, seed mass and other species-specific traits may be better predictors for idiosyncratic variation in seedling establishment than status. Our data support the fluctuating resource hypothesis and demonstrate that the reserve effect of seeds may facilitate seedling emergence. The direct comparison of propagule pressure with other environmental factors showed that propagule pressure affects absolute seedling abundance, which may be crucial for species that depend on other

  4. Thalli Growth, Propagule Survival, and Integrated Physiological Response to Nitrogen Stress of Ramalina calicaris var. japonica in Shennongjia Mountain (China

    Directory of Open Access Journals (Sweden)

    Chuan-Hua Wang

    2018-05-01

    Full Text Available In this study, effects of nitrogen (N availability on growth, survival of Ramalina calicaris var. japonica, and whether it respond nitrogen stress in an integrated physiological way was evaluated. Thalli growth and propagule survival, thalli N and phosphorus (P content, and activity of phosphomonoesterase (PME of R. calicaris var. japonica were determined in a field experiment. Its differentiate adsorption in ammonia and nitrate, the activity of glutamine synthetase (GSA and nitrate reductase (NRA also were investigated in a series of indoor experiments. The results showed that N deposition significantly decreased the growth and survival of this lichen, and the N sensitivity threshold was suggested at 6.0 kg N⋅ha-1⋅y-1. When the N deposition increased from 8.59 kg N⋅ha-1⋅y-1 to 14.24, 20.49, 32.99 and 57.99 kg N⋅ha-1⋅y-1, the growth rates of lichen thalli decreased by 26.47, 39.01, 52.18 and 60.3%, respectively; Whereas the survival rate of the lichen propagules decreased from 92.8% of control (0.0 kg N⋅ha-1⋅y-1 to 10.7% of 50.0 kg N⋅ha-1⋅y-1, when they were treated with 0.00, 6.25, 12.5, 25.0, and 50.0 kg N⋅ha-1⋅y-1 deposition. Compared with an adequate adsorption of ammonium N, no nitrate adsorption occurred when thalli was submerged in solution lower than 0.4 mM. Our results also suggested that thalli total nitrogen, N:P ratio increased with N availability, and the activity of PME was significantly correlated with thalli total nitrogen. These all indicated that phosphorus limitation occurred when R. calicaris var. japonica treated with higher nitrogen deposition. Compared with slightly effects of NRA, GSA of R. calicaris var. japonica responded nitrogen availability significantly; In addition, GSA and NRA negatively correlated with thalli growth rate and propagule survival significantly. These results indicated that nitrogen stress do decrease growth and survival of R. calicaris var. japonica, and lichen would be

  5. Vascular plant propagule banks of six eastern hemlock stands and potential response to the hemlock woolly adelgid in the Catskill Mountains of New York

    Science.gov (United States)

    Thad E. Yorks; Donald J. Leopold; Dudley J. Raynal

    2000-01-01

    We examined propagule banks in six eastern hemlock (Tsuga canadensis (L.) Carriere) stands in the Catskill Mountains of New York. These stands are at risk of mortality due to the hemlock woolly adelgid (Adelges tsugae Annand), but potential effects of mortality on species composition are uncertain.

  6. Humid microclimates within the plumage of mallard ducks (Anas platyrhynchos) can potentially facilitate long distance dispersal of propagules

    Science.gov (United States)

    Coughlan, Neil E.; Kelly, Tom C.; Davenport, John; Jansen, Marcel A. K.

    2015-05-01

    Birds as carriers of propagules are major agents in the dispersal of plants, animals, fungi and microbes. However, there is a lack of empirical data in relation to bird-mediated, epizoochorous dispersal. The microclimate found within the plumage likely plays a pivotal role in survival during flight conditions. To investigate the potential of epizoochory, we have analysed the microclimatic conditions within the plumage of mallard ducks (Anas platyrhynchos). Under similar ambient conditions of humidity and temperature, a sample of mallards showed a consistent microclimatic regime with variation across the body surface. The highest (mean) temperature and specific humidity occurred between feathers of the postpatagium. The lowest humidity was found between feathers of the centre back and the lowest temperature in the crissum. Observed differences in plumage depth and density, and distance from the skin, are all likely to be determining factors of microclimate condition. Specific humidity found within the plumage was on average 1.8-3.5 times greater than ambient specific humidity. Thus, the plumage can supply a microclimate buffered from that of the exterior environment. Extrapolating survival data for Lemna minor desiccation at various temperature and humidity levels to the measured plumage microclimatic conditions of living birds, survival for up to 6 h can be anticipated, especially in crissum, crural and breast plumage. The results are discussed in the context of potential long distance epizoochorous dispersal by A. platyrhynchos and similar species.

  7. Evaluation Of GAMMA And Sodium Azide Radiation Looking For Resistance To MACROPHOMINA Phaseoli T. In Three Promissory Lines Of Benne Sesamum Indicum L

    International Nuclear Information System (INIS)

    Lopez R, Liliana V.; Melo O, Mario E.; Reina C, Yasmin

    1993-01-01

    The Benne in Colombia is a cultivation relegated to small properties and its main problem is the withering (Macrophomina phaseoli T.) which may cause losses of the cent per cent. Situation that generated the interest to carry out a study on induction of mutations in this species, using Gamma Rays and Sodium Azide with the purpose of obtaining possible resistant mutants to the mushroom. The initial stage of the work, determination of good dose, was developed in the INEA in Bogota and the field evaluation in the ICA Nataima in Espinal. A rehearsal was mounted to evaluate germination and plants height in the lines Cycle 0 - PlO, ENA 841-3 and ENA 841-5 tried with the doses (OR, 25, 50, 75 and 100) krad of gamma rays and (OR, 5, 10, 15 and 20) mm of Sodium Azide, the obtained information was processed using a Complete Blocks design at random with Factorial arrangement 3x5 and test of Duncan, based on the obtained data the Curves of Radio and chemical sensitivity were determined. Then the massive treatment of the seed was made with the optimum mutagenic dose and it was taken to field (Ml), giving it good conditions for the development of the cultivation. The test of chlorophyll ian mutants was applied to the seed harvested M2 to select the treatment with which the program of improvement should continue, it was sowed in a lot with high pressure of selection of the mushroom and an inter and intra family selection was made

  8. Analysis and simulation of propagule dispersal and salinity intrusion from storm surge on the movement of a marsh–mangrove ecotone in South Florida

    Science.gov (United States)

    Jiang, Jiang; DeAngelis, Donald L.; Anderson, Gordon H.; Smith, Thomas J.

    2014-01-01

    Coastal mangrove–freshwater marsh ecotones of the Everglades represent transitions between marine salt-tolerant halophytic and freshwater salt-intolerant glycophytic communities. It is hypothesized here that a self-reinforcing feedback, termed a “vegetation switch,” between vegetation and soil salinity, helps maintain the sharp mangrove–marsh ecotone. A general theoretical implication of the switch mechanism is that the ecotone will be stable to small disturbances but vulnerable to rapid regime shifts from large disturbances, such as storm surges, which could cause large spatial displacements of the ecotone. We develop a simulation model to describe the vegetation switch mechanism. The model couples vegetation dynamics and hydrologic processes. The key factors in the model are the amount of salt-water intrusion into the freshwater wetland and the passive transport of mangrove (e.g., Rhizophora mangle) viviparous seeds or propagules. Results from the model simulations indicate that a regime shift from freshwater marsh to mangroves is sensitive to the duration of soil salinization through storm surge overwash and to the density of mangrove propagules or seedlings transported into the marsh. We parameterized our model with empirical hydrologic data collected from the period 2000–2010 at one mangrove–marsh ecotone location in southwestern Florida to forecast possible long-term effects of Hurricane Wilma (24 October 2005). The model indicated that the effects of that storm surge were too weak to trigger a regime shift at the sites we studied, 50 km south of the Hurricane Wilma eyewall, but simulations with more severe artificial disturbances were capable of causing substantial regime shifts.

  9. Understanding the biological invasion risk posed by the global wildlife trade: propagule pressure drives the introduction and establishment of Nearctic turtles.

    Science.gov (United States)

    García-Díaz, Pablo; Ross, Joshua V; Ayres, César; Cassey, Phillip

    2015-03-01

    Biological invasions are a key component of human-induced global change. The continuing increase in global wildlife trade has raised concerns about the parallel increase in the number of new invasive species. However, the factors that link the wildlife trade to the biological invasion process are still poorly understood. Moreover, there are analytical challenges in researching the role of global wildlife trade in biological invasions, particularly issues related to the under-reporting of introduced and established populations in areas with reduced sampling effort. In this work, we use high-quality data on the international trade in Nearctic turtles (1999-2009) coupled with a statistical modelling framework, which explicitly accounts for detection, to investigate the factors that influence the introduction (release, or escape into the wild) of globally traded Nearctic turtles and the establishment success (self-sustaining exotic populations) of slider turtles (Trachemys scripta), the most frequently traded turtle species. We found that the introduction of a species was influenced by the total number of turtles exported to a jurisdiction and the age at maturity of the species, while the establishment success of slider turtles was best associated with the propagule number (number of release events), and the number of native turtles in the jurisdiction of introduction. These results indicate both a direct and indirect association between the wildlife trade and the introduction of turtles and establishment success of slider turtles, respectively. Our results highlight the existence of gaps in the number of globally recorded introduction events and established populations of slider turtles, although the expected bias is low. We emphasize the importance of researching independently the factors that affect the different stages of the invasion pathway. Critically, we observe that the number of traded individuals might not always be an adequate proxy for propagule pressure

  10. Management of foliar and soilborne pathogens of cowpea ( Vigna ...

    African Journals Online (AJOL)

    White and pink garlic extracts were tested for their antifungal potentials on mycelial radial growth, spores and sclerotial production of Macrophomina phaseolina (Tassi) Goid, Colletotrichum destructivum O gara and Colletotrichum capsici (Syd) Butler and Bisby pathogens of cowpea in vitro. Water or ethanol extracts of ...

  11. Aqueous and ethanolic extracts of Vernonia amygdalina L. in the ...

    African Journals Online (AJOL)

    A study was carried out on the use of Vernonia amygdalina del. extract to control fungi associated with groundnut (Arachis hypogeae L) seeds. Aspergillus niger van Tiegh, A. flavus link ex fries, Cercospora arachidicola Hori, Phoma exigua desm., Macrophomina phaseolina (Tassi) Goid, Fusarium oxysporium schl., ...

  12. (Cucumis melo L.) cultivars to soil-borne plant pathogenic fungi in Iran

    African Journals Online (AJOL)

    ajl11

    2012-10-30

    Oct 30, 2012 ... Melon is an important dessert fruit in the Sistan region of. Iran, but its cultivation is threatened by attacks of. Macrophomina phaseolina (Tassi), Monosporascus cannonballus (Pollack and Uecker) and Rhizoctonia solani (Kuhn) (Safarnezhad, 2004). Melon death induced by these soil-borne plant pathogenic ...

  13. Efficacy of Jatropha, Annona and Parthenium biowash on ...

    African Journals Online (AJOL)

    ... rot in chickpea) and Macrophomina phaseolina (causes charcoal rot in sorghum). ... crude biowash was also passed through C18 solid phase extraction cartridges and ... When the organic fraction of Jatropha biowash was further fractionated by ... Hence, it was concluded that one of these three bands could be the active

  14. Increases in snap bean and soybean seedling diseases associated with a chloride salt and changes in the micro-partitioning of tap root calcium

    Science.gov (United States)

    In a series of field experiments from 1995 through 2010, the incidence of seedling diseases of snap bean and soybean caused by Rhizoctonia solani, Macrophomina phaseolina, Pythium spp., and Fusarium spp. was greater with an application of KCl than with K2SO4 applied at 93 kg K/ha. To determine if th...

  15. Biocontrol of charcoal-rot of sorghum by actinomycetes isolated from ...

    African Journals Online (AJOL)

    use

    2011-12-12

    Dec 12, 2011 ... Streptomyces but with different species in BLAST analysis. This study indicates that the selected actinomycetes have the potential for PGP and control of charcoal-rot disease in sorghum. Key words: Antagonistic actinomycetes, biocontrol, charcoal-rot, Macrophomina phaseolina. INTRODUCTION.

  16. Evaluation of antagonistic fungi against charcoal rot of sunflower ...

    African Journals Online (AJOL)

    In vitro, sensitivity of Macrophomina phaseolina (Tassi) Goid determined through inhibition zone technique to various antagonistic fungi viz., Aspergillus niger, Aspergillus flavus, Trichoderma viride, Trichoderma harzianum and Penicillium capsulatum amended into PDA medium. All the antagonists reduced the colony ...

  17. Antifungal activity of aqueous and methanolic extracts of some seaweeds against common soil-borne plant pathogenic fungi

    International Nuclear Information System (INIS)

    Khan, S.A.; Abid, M.; Hussain, F.

    2017-01-01

    Total 32 species of different seaweeds belonging to Chlorophyta, Phaeophyta and Rhodophyta were collected from the coast of Karachi, Pakistan to investigate their antifungal activity. Most of the seaweeds inhibited growth of Fusarium oxypsorum, Macrophomina phaseolina and Rhizoctonia solani. The highest antifungal activities were observed in Sargasssum tenerrimum in both aqueous and methanolic extracts as compared to other seaweeds. (author)

  18. Temporal Genetic Variance and Propagule-Driven Genetic Structure Characterize Naturalized Rainbow Trout (Oncorhynchus mykiss) from a Patagonian Lake Impacted by Trout Farming.

    Science.gov (United States)

    Benavente, Javiera N; Seeb, Lisa W; Seeb, James E; Arismendi, Ivan; Hernández, Cristián E; Gajardo, Gonzalo; Galleguillos, Ricardo; Cádiz, Maria I; Musleh, Selim S; Gomez-Uchida, Daniel

    2015-01-01

    Knowledge about the genetic underpinnings of invasions-a theme addressed by invasion genetics as a discipline-is still scarce amid well documented ecological impacts of non-native species on ecosystems of Patagonia in South America. One of the most invasive species in Patagonia's freshwater systems and elsewhere is rainbow trout (Oncorhynchus mykiss). This species was introduced to Chile during the early twentieth century for stocking and promoting recreational fishing; during the late twentieth century was reintroduced for farming purposes and is now naturalized. We used population- and individual-based inference from single nucleotide polymorphisms (SNPs) to illuminate three objectives related to the establishment and naturalization of Rainbow Trout in Lake Llanquihue. This lake has been intensively used for trout farming during the last three decades. Our results emanate from samples collected from five inlet streams over two seasons, winter and spring. First, we found that significant intra- population (temporal) genetic variance was greater than inter-population (spatial) genetic variance, downplaying the importance of spatial divergence during the process of naturalization. Allele frequency differences between cohorts, consistent with variation in fish length between spring and winter collections, might explain temporal genetic differences. Second, individual-based Bayesian clustering suggested that genetic structure within Lake Llanquihue was largely driven by putative farm propagules found at one single stream during spring, but not in winter. This suggests that farm broodstock might migrate upstream to breed during spring at that particular stream. It is unclear whether interbreeding has occurred between "pure" naturalized and farm trout in this and other streams. Third, estimates of the annual number of breeders (Nb) were below 73 in half of the collections, suggestive of genetically small and recently founded populations that might experience substantial

  19. Experimental tests of priority effects and light availability on relative performance of Myriophyllum spicatum and Elodea nuttallii propagules in artificial stream channels.

    Directory of Open Access Journals (Sweden)

    Emily P Zefferman

    Full Text Available Submersed macrophytes have important ecological functions in many streams, but fostering growth of beneficial native species while suppressing weedy invasives may be challenging. Two approaches commonly used in management of terrestrial plant communities may be useful in this context: (1 altering resource availability and (2 establishing desirable species before weeds can invade (priority effects. However, these approaches are rarely used in aquatic systems, despite widespread need for sustainable solutions to aquatic weed problems. In artificial stream channels in California, USA, I conducted experiments with asexual propagules of non-native invasive Myriophyllum spicatum (Eurasian watermilfoil and native Elodea nuttallii (western waterweed to address the questions: (1 How does light availability affect relative performance of the two species?; (2 Does planting the native earlier than the invasive decrease survival or growth rate of the invasive?; and (3 Do light level and priority effects interact? The relative performance between E. nuttallii and M. spicatum had an interesting and unexpected pattern: M. spicatum had higher growth rates than E. nuttallii in the zero and medium shade levels, but had similar performance in the low and high shade levels. This pattern is most likely the result of E. nutallii's sensitivity to both very low and very high light, and M. spicatum's sensitivity to very low light only. Native priority did not significantly affect growth rate or survival of M. spicatum, possibly because of unexpectedly poor growth of the E. nuttallii planted early. This study suggests that altering light levels could be effective in reducing growth of an invasive macrophyte, and for changing the competitive balance between a native and a non-native species in the establishment phase. Further investigations into the use of priority effects and resource alteration for submersed macrophyte management are warranted, given their mixed results

  20. Experimental tests of priority effects and light availability on relative performance of Myriophyllum spicatum and Elodea nuttallii propagules in artificial stream channels.

    Science.gov (United States)

    Zefferman, Emily P

    2015-01-01

    Submersed macrophytes have important ecological functions in many streams, but fostering growth of beneficial native species while suppressing weedy invasives may be challenging. Two approaches commonly used in management of terrestrial plant communities may be useful in this context: (1) altering resource availability and (2) establishing desirable species before weeds can invade (priority effects). However, these approaches are rarely used in aquatic systems, despite widespread need for sustainable solutions to aquatic weed problems. In artificial stream channels in California, USA, I conducted experiments with asexual propagules of non-native invasive Myriophyllum spicatum (Eurasian watermilfoil) and native Elodea nuttallii (western waterweed) to address the questions: (1) How does light availability affect relative performance of the two species?; (2) Does planting the native earlier than the invasive decrease survival or growth rate of the invasive?; and (3) Do light level and priority effects interact? The relative performance between E. nuttallii and M. spicatum had an interesting and unexpected pattern: M. spicatum had higher growth rates than E. nuttallii in the zero and medium shade levels, but had similar performance in the low and high shade levels. This pattern is most likely the result of E. nutallii's sensitivity to both very low and very high light, and M. spicatum's sensitivity to very low light only. Native priority did not significantly affect growth rate or survival of M. spicatum, possibly because of unexpectedly poor growth of the E. nuttallii planted early. This study suggests that altering light levels could be effective in reducing growth of an invasive macrophyte, and for changing the competitive balance between a native and a non-native species in the establishment phase. Further investigations into the use of priority effects and resource alteration for submersed macrophyte management are warranted, given their mixed results in other

  1. Banks of microscopic forms and survival to darkness of propagules and microscopic stages of macroalgae Bancos de formas microscópicas y supervivencia a la oscuridad de propágulos y formas microscópicas de macroalgas

    Directory of Open Access Journals (Sweden)

    BERNABÉ SANTELICES

    2002-09-01

    Full Text Available Previous studies have found that the number of species conforming a bank of microscopic forms in tide pools in central Chile accounted only for half the number of species present in the macroscopic vegetation around the pools. An elemental condition for survival in these banks is the ability of microscopic forms to tolerate darkness or very low irradiances for extended periods. To test this ability, spores of 17 green, brown and red algal species, present and absent from the bank, were incubated at different combinations of irradiances and day lengths. Propagules of 47 % of the species tested (eight species germinated in total darkness while the propagules of the other nine species germinated under conditions of very low irradiance (2-10 µmol m-2 s-1. In most species, microforms showed a higher tolerance to darkness than the propagules. Some survived for over a year and one species (Gelidium lingulatum could live under complete darkness for 500 days. The ability to survive in total darkness did not relate to presence or absence of a species in the banks of microscopic forms previously studied, to phylogenetic relatedness, life history style, propagule size, morphology of microscopic forms or to successional status (fugitive versus late successional. Thus, tolerance to darkness appears to be common to propagules and microscopic stages of most benthic algae. The growth patterns exhibited by the microforms of Lessonia nigrescens, Chaetomorpha firma and Glossophora kunthii suggest high irradiances on these recruits might determine the shallower limits of distribution of these speciesEstudios previos han encontrado que el número de especies formando un banco de formas microscópicas en pozas de mareas de Chile central incluyó sólo la mitad del número de especies presentes en la vegetación macroscópica en las cercanías de las pozas intermareales. Una primera condición para sobrevivir en estos bancos radica en la capacidad de las formas

  2. Propagules removal in fragments of native forest and in reforested areas in an Araucaria Forest region of Paraná State Remoção de propágulos em fragmento de floresta nativa e reflorestamentos numa região de Floresta Ombrófila Mista do estado do Paraná

    Directory of Open Access Journals (Sweden)

    Yves Rafael Bovolenta

    2011-06-01

    Full Text Available A question that has been discussed is the role that reforestations with exotic species in native fauna and several studies have shown that removal of propagules is lower in these environments. This study compared the removal rate of propagules (araucaria seeds, peanuts, corn from areas of native forest (FN, reforestations of Pinus taeda L. (RP, Eucalyptus saligna Sm. (RE and Araucaria angustifolia (Bertol Kuntze (RA. In FN all propagules were removed. There was no difference in the removal of araucaria seeds between FN and RA, and removal rate in both areas differ from the removal rate in the RP and RE. In RP there was high removal of peanuts, while the RE showed the lowest value of removal of the three propagules. The low removal rates in reforestation of pine and eucalyptus reflect the decreased exploitation of these habitats for wildlife, which may be related to a poorly structured understory. Uma questão que tem sido discutida é o papel das monoculturas florestais exóticas na manutenção da fauna nativa e vários estudos têm mostrado que a remoção de propágulos é menor nesses ambientes. O presente trabalho comparou a taxa de remoção de propágulos (pinhão, amendoim, milho entre áreas de Floresta Nativa (FN, Reflorestamentos de Pinus taeda L. (RP, de Eucalyptus saligna Sm. (RE e Araucaria angustifolia (Bertol Kuntze (RA. Na FN, todos os propágulos foram removidos e não houve diferença significativa na remoção de pinhão entre a FN e o RA. A remoção de propágulos nessas áreas diferiu da remoção no RP e RE. No RP, houve alta remoção de amendoim, enquanto que o RE apresentou os menores valores de remoção dos três propágulos. As baixas taxas de remoção nos reflorestamentos de pinus e eucalipto refletem a menor exploração desses habitas pela fauna, o que pode estar relacionado com um subosque pouco estruturado.

  3. Effect of (/sup 60/cobalt) gamma rays on growth and root rot diseases in mungbean (vigna radiata L.)

    International Nuclear Information System (INIS)

    Ikram, N.; Dawar, S.; Zaki, M.J.; Abass, Z.

    2010-01-01

    Present investigation showed that gamma rays influences suppressive effect on root rot fungi such as Macrophomina phaseolina (Tassi) Goid, Rhizoctonia solani Kuhn and Fusarium spp., and inducive effect on growth parameters of mung bean (Vigna radiata L.). Seeds of mung bean were treated with gamma rays (/sup 60/Cobalt) at time periods of 0 and 4 minutes and stored for 90 days at room temperature to determine its effect on growth parameters and infection of root infecting fungi. All treatments of gamma rays enhanced the growth parameters as compared to untreated plants. Infection of M. phaseolina, R. solani and Fusarium spp., were significantly decreased on mung bean seeds treated with gamma rays. Gamma rays significantly increased the growth parameters and controlled the root rot fungi up to 90 days of storage of seeds. (author)

  4. Management of root rot and root knot disease of mungbean with the application of mycorrhizospheric fluorescent pseudomonas under field condition

    International Nuclear Information System (INIS)

    Bokhari, S.S.; Tariq, S.; Ali, S.A.

    2014-01-01

    The mycorrhizosphere is the region around a mycorrhizal fungus in which nutrients released from the hyphae increases microbial population and its activities. In this study five mycorrhizospheric fluorescent Pseudomonas (MRFP) were evaluated for biocontrol potential under field condition using mungbean (Vigna radiata) as test plant. MRFP-249 significantly reduced Fusarium solani, Rhizoctonia solani and Macrophomina phaseolina. Whereas MRFP246 and MRFP-247 were also found effective against M. phaseolina. Mycorrhizospheric fluorescent Pseudomonas were also found effective against root knot nematode by reducing the galls on roots and nematode's penetration in roots. Highest fresh shoot weight and plant height was produced by MRFP-248. Plants grown in soil treated with Pseudomonas showed higher number of VAM spores around the mungbean roots than untreated control plants. The mycorrhizal symbiosis should not be considered merely as bipartite, plant-fungus interaction, but should instead include the associated microorganisms, particularly fluorescent Pseudomonas. (author)

  5. Enzimas extracelulares da família Botryosphaeriaceae

    OpenAIRE

    Pinheiro, Ana Rita Almeida

    2015-01-01

    As espécies da família Botryosphaeriaceae são morfologicamente diversas e descritas como endofíticas, patogénias e saprófitas. Estas são normalmente encontradas numa grande diversidade de hospedeiros. Os fungos patogénicos para plantas Macrophomina phaseolina, Neofusicoccum parvum e Diplodia corticola secretam uma variedade de enzimas extracelulares, tais como proteases e glicosil hidrolases, algumas das quais envolvidas na interação hospedeiro-patogénio. A fim de elucidar a correlação ent...

  6. Evaluation des rendements en graines et fanes des variétés

    African Journals Online (AJOL)

    (L.) Walp.) au Niger avec mention spéciale au Macrophomina phaseolina (Tassi) Goid. Thèse de doctorat, Université de Niamey,. 117p. Addam K. S. 1999. Effet de l'azote et du phosphore sur la nutrition azotée des variétés de niébé. (Vigna unguiculata (L.) Walp.) présélection- nées au Niger. DEA, physiologie végétale.

  7. Butyrylcholinesterase, lipoxygenase inhibiting and antifungal alkaloids from Isatis tinctoria.

    Science.gov (United States)

    Ahmad, Ijaz; Fatima, Itrat

    2008-06-01

    Phytochemical investigations on the alkaloidal fraction of the whole plant of the Isatis tinctoria led to the isolation of the alkaloids 1-6. Compounds 3, 2 were found to be potent butyrylcholinesterase and lipoxygenase enzymes inhibitors in a concentration-dependent manner with the IC(50) values 16.3 +/- 0.06 and 19.7 +/- 0.03 microM against BChE and 30.6 +/- 0.02 and 33.7 +/- 0.05 microM against LOX, respectively. The compounds (1-6) showed significant antifungal activity against Trichophyton schoen leinii, Aspergillus niger, Candida albicans, Trichophyton simii, and Macrophomina phaseolina.

  8. Propágulos de fungos micorrízicos arbusculares em solos deficientes em fósforo sob diferentes usos, da região semi-arida no nordeste do Brasil Propagules of arbuscular mycorrhizae in p-deficient soils under different land uses, in semi-arid NE Brazil

    Directory of Open Access Journals (Sweden)

    Regina Lúcia Félix de Aguiar Lima

    2007-04-01

    Full Text Available A conversão de áreas de caatinga em agricultura e pecuária de subsistência é uma das características marcantes da região semi-árida do Nordeste do Brasil. O presente estudo investigou o efeito dessa conversão sobre os propágulos de fungos micorrízicos arbusculares (FMA em 10 locais diferentes, distribuídos nos Estados da Paraíba e de Pernambuco. Cada local consistiu de uma área de vegetação nativa (caatinga contígua com uma área cultivada, na mesma posição de encosta. Amostras de solo foram coletadas a intervalos de 20-30 m, nas profundidades de 0-7,5 e 7,5-15 cm (10 locais x 2 usos do solo x 2 profundidades com 4 pontos amostrais ao longo de uma transecção que cruzava as áreas contíguas. As raízes (The conversion of tropical dry forest into areas used for subsistence agriculture or livestock production is a common feature of the semi-arid region of NE Brazil. Our study looked into the effect of these land use changes on propagules of arbuscular mycorrhizal fungi (AMF at ten sites distributed in the states of Paraíba and Pernambuco. Each site consisted of an area under native vegetation (Dry-Forest adjacent to a cultivated area in the same slope position. Soil samples were taken at distance intervals of 20-30 m from two depths (0-7.5 and 7.5-15 cm along a transect crossing the adjacent areas (10 sites x 2 land uses x 2 depths x 4 sampling points. Roots (< 2 mm found in the soil samples (n = 160 were stained with trypan blue to assess the percentage of AMF colonization as well as the type of fungal structures. The AMF spores were separated from soil by wet sieving, incubated in iodonitrotetrazolium chloride (INT solution and counted; those stained with INT were considered viable. Soil samples were analyzed for resin-extractable P and total organic carbon (TOC. For data analysis, the 10 areas under dry forest were separated in two sub-groups: Undisturbed-Dry-Forest (UDF, n = 6 and Disturbed-Dry-Forest (DDF, n = 4, owing

  9. Mycorrhizal Propagule Persistence in a Succession of Cereals in a Disturbed and Undisturbed Andisol Fertilized with Two Nitrogen Sources Persistencia de Propágulos Micorrícicos en una Sucesión de Cereales en un Andisol Disturbado y no Disturbado, Fertilizado con Dos Fuentes de Nitrógeno

    Directory of Open Access Journals (Sweden)

    Pablo Cornejo

    2009-09-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF form symbiosis with plant roots, improving its establishment, nutrition, and tolerance to adverse soil conditions. In annual crop rotations, some aspects such as the type of N fertilizer and tillage system used can affect the AMF propagule density and its functionality in the following crop. To analyze the effect of the agronomic practices previously mentioned on the persistence and density of AMF propagules, a study in a succession of cereals was carried out. For this, soil previously cropped with wheat (Triticum aestivum L. and fertilized with urea (NH4+ or sodium nitrate (NO3- was disturbed in each case by simulating conventional tillage (CT or maintained without disturbing, simulating no-tillage (NT. It was then cultivated with oat (Avena sativa L. using the same N sources. Higher densities of AMF active mycelium and colonized root length in the NT soil were observed (76 and 497% higher than in CT soil, respectively, P Los hongos micorrícico-arbusculares (AMF forman simbiosis con las raíces de las plantas, favoreciendo su establecimiento, nutrición y tolerancia a condiciones adversas del suelo. En rotaciones de cultivos anuales algunos aspectos como el tipo de fertilizante nitrogenado utilizado y el sistema de labranza pueden afectar la densidad de propágulos de AMF y su funcionalidad en el cultivo siguiente. Para analizar el efecto de las prácticas agronómicas previamente mencionadas sobre la persistencia y densidad de los propágulos de AMF, se realizó un estudio en microcosmos simulando una rotación de cereales. Para esto, suelo previamente cultivado con trigo (Triticum aestivum L. y fertilizado con urea (NH4+ o nitrato de sodio (NO3- fue, en cada caso, disturbado simulando una labranza convencional (CT o mantenido sin disturbar simulando cero labranza (NT y cultivado con avena (Avena sativa L., utilizando las mismas fuentes de N. Se observaron mayores densidades de micelio activo de AMF y

  10. Anti-fungal activity of some medicinal plants on different pathogenic fungi

    International Nuclear Information System (INIS)

    Hussain, F.; Abid, M.; Farzana, A.; Shaukat, S.; Akbar, M.

    2015-01-01

    The antifungal activity of different medicinal and locally available plants extracts (leaves, fruit, seeds) which are usually found in the surrounding of fields or in the fields on some fungi were tested in lab conditions. Six different plants were selected for testing these plants were Acacia nilotica (Lamk.) Willd. Azadirachta indica (A.) Juss. Crotalaria juncea L. Eucalyptus camaldulensis Dehnh. Ocimum basilicum L. and Prosopis juliflora (Sw.) Dc. These plants showed antifungal activity against the Aspergillus flavus, A. niger, Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani. These plants crude extracts of leaves showed inhibition activity against the fungi and suppressed the myclial growth. Over all selected plants exhibited moderate type of inhibition against these above mentioned pathogens. Among these plants, Azadirachta indica, Ocimum basilicum and Crotalaria juncea showed the most effective results against the Aspergillus, Fusarium and Rhizoctonia sp. of fungal pathogens. Whereas, Acacia nilotica, Eucalyptus camaldulensis and Prosopis juliflora showed least potential of inhibition against all above mentioned fungal pathogens. It is investigated in present studies that Azadirachta indica, Ocimum basilicum and Crotalaria juncea can be utilized against the management of fungal diseases particularly Aspergillus flavus, A. niger, Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani. (author)

  11. Antifungal and antibacterial activity of endophytic penicillium species isolated from salvadora species

    International Nuclear Information System (INIS)

    Korejo, F.; Shafique, H.A.; Haque, S.E.; Ali, S.A.

    2014-01-01

    Salvadora persica and S. S.oleoides are facultative holophytic plants, well known as miswak, are traditionally used to ensure oral hygiene among Muslim people in Asian and African counties. Species of Salvadora have a number of proven pharmacological importance. Besides, terrestrial fungi endophytic fungi are also gaining importance for the isolation of bioactive compounds. In this study 74 samples (root, shoot and leaves) from S. persica and S. oleoides were examined for endophytic fungi, 22 samples showed presence of Penicillium spp., 48 were found positive for aspergilli, whereas 10 samples showed infection of Fusarium solani, 4 were found infected with Macrophomina phaseolina and one with Rhizoctonia solani. Most of the Penicillium isolated were identified as P. restrictum, P. citrinum and P. canescens. In dual culture plate assay out of four Penicillium isolates tested, P. citrinum and one isolate of P. restrictum caused growth inhibition of all four test root rotting fungi, Fusarium solani, F. oxysporum, Macrophomina phaseolina and Rhizoctonia solani. Culture filtrates of Penicillium spp., were also evaluated against four common laboratory bacteria namely Bacillus subtilis, Staphylococcus aureus, Salmonella typhimurium and Escherichia coli and above mentioned root rotting fungi. Culture filtrates of endophytic Penicillium spp., also showed significant antibacterial and antifungal activity. Secondary metabolites of endophytic Penicillium spp., offer an exciting area of research for the discovery of novel antimicrobial compounds. (author)

  12. Efficacy of wild plant in combination with microbial antagonists for the control of root rot fungi on mungbean and cowpea

    International Nuclear Information System (INIS)

    Ikram, N.; Dawar, S.

    2015-01-01

    Present work was carried out to investigate the efficacy of Aerva javanica in combination with different microbial antagonists namely Rhizobium meliloti, Pseudomonas aeruginosa, Trichoderma harzianum and Aspergillus niger. Soil amended with A. javanica stem, leaves, flower powder at the rate1% w/w and seeds of cowpea (Vigna unguiculata L.) and mungbean (Vigna radiata L.) were coated with microbial antagonists for the control of root infecting fungi like Macrophomina phaseolina (Tassi) Goid, Fusarium spp. and Rhizoctonia solani Kiihn. Infection of M. phaseolina and R. solani were completely suppressed when seeds were coated with P. aeruginosa, T. harzianum, A. niger, R. meliloti and A. javanica leaves powder mixed in soil at the rate 1% w/w. All antagonists showed reduction in combination with A. javanica leaves powder at the rate1% but T. harzianum and P. aeruginosa in combination with A. javanica leaves showed promising results in complete reduction of R. solani and M. phaseolina on both crops. All growth parameters were maximum when soil was amended with A. javanica leaves powder at the rate 1% w/w and seeds were coated with T. harzianum and P. aeruginosa. (author)

  13. (Ipomoea batatas L.) AS INFLUENCED BY PROPAGULE LENGTH

    African Journals Online (AJOL)

    Key words: economic analysis, growth variables, organic fertilizer, tuber yield. INTRODUCTION ..... ns - not significant at 5% level of probability. Table 3: Vine girth (cm) of sweet ..... production couple with longer vines. The significant increase ...

  14. Effect of ageing on survival of benthic diatom propagules

    Digital Repository Service at National Institute of Oceanography (India)

    Anil, A.C.; Mitbavkar, S.; De; Hegde, S.; De; Meher, S.S.; Banerjee, D.

    unfavorable for vegetative growth, many diatoms form resting stages to survive cell degradation or death (Anderson, 1975; Malone, 1980; Hargraves and French, 1983; Fryxell, 1990). Various external factors like availability of nutrients (N, P, Fe, Si.... 128, 497-508. 15 Lewis, J., Harris, A.S.D., Jones, K.J., Edmonds, R.L., 1999. Long-term survival of marine planktonic diatoms and dinoflagellates in stored sediment samples. J. Plank. Res. 21, 343- 354. Malone, T.C., 1980. Algal size. In...

  15. Ação do óleo essencial de Syzygium aromaticum (L. Merr. & L.M.Perry sobre as hifas de alguns fungos fitopatogênicos Action of Syzygium aromaticum (L. Merr. & L.M.Perry essential oil on the hyphae of some phytopathogenic fungi

    Directory of Open Access Journals (Sweden)

    A.R.T Costa

    2011-01-01

    Full Text Available Atualmente o uso de métodos alternativos para o controle de doenças e pragas na agricultura, visando minimizar os danos ao meio ambiente e à saúde pública é uma prática reconhecida e necessária. Este trabalho objetivou investigar a ação do óleo essencial de Syzygium aromaticum (L. Merr. & L.M.Perry sobre o crescimento micelial in vitro dos fungos fitopatogênicos Rhizoctonia solani, Fusarium solani, Fusarium oxysporum e Macrophomina phaseolina. A análise por cromatografia gasosa acoplada com espectrometria de massa possibilitou a identificação de eugenol (83,6%, acetato de eugenila (11,6% e cariofileno (4,2%. A avaliação microscópica dos micélios dos fungos evidenciou diversas alterações morfológicas, como a presença de vacúolos, desorganização dos conteúdos celulares, diminuição na nitidez da parede celular, intensa fragmentação e menor turgência das hifas. O óleo essencial de cravo apresentou atividade fungicida na concentração de 0,15% sobre o crescimento de R. solani, F. oxysporum e F. solani, entretanto não demonstrou essa atividade sobre M. phaseolina. Esses resultados indicam perspectivas favoráveis para posterior uso do óleo de cravo no controle desses fitopatógenos na agricultura.Currently, the use of alternative methods to control diseases and pests in agriculture has been a recognized and necessary practice to minimize damages to the environment and public health. This study aimed to investigate the action of clove [Syzygium aromaticum (L. Merr. & L.M.Perry] essential oil on the in vitro mycelial growth of the phytopathogenic fungi Rhizoctonia solani, Fusarium solani, Fusarium oxysporum and Macrophomina phaseolina. Analysis by gas chromatography-mass spectrometry allowed the identification of eugenol (83.6%, eugenyl acetate (11.6% and caryophyllene (4.2%. Microscopic evaluation of mycelia showed several morphological changes such as presence of vacuoles, cell content disorganization, decreased

  16. Inhibition of in vitro growth of soil-borne pathogens by compost-inhabiting indigenous bacteria and fungi

    International Nuclear Information System (INIS)

    Ramzan, N.; Noreen, N.; Shahzad, S.

    2014-01-01

    During the present studies, compost-inhabiting microorganisms including 44 fungi and 15 bacteria isolated from different compost samples were evaluated for their in vitro efficacy against soil-borne pathogens viz., Fusarium solani, Macrophomina phaseolina, Pythium aphanidermatum, Rhizoctonia solani, and Sclerotium rolfsii. Compost inhabiting microbes like Trichoderma harzianum, T. virens, Bacillus cereus, B. pumilus, B. subtilis, Micrococcus varians and Pseudomonas fluorescens were found to inhibit all the test pathogens. Acrophialophora fusispora and Penicillium citrinum reduced the mycelial growth of all the test pathogens except Sclerotium rolfsii. Bacillus licheniformis and Bacillus megaterium showed biocontrol activity against all the pathogens except Rhizoctonia solani. Trichoderma harzianum parasitized mycelia of all the tested pathogens and produced coiling around the mycelium. (author)

  17. Comparative Methods of Application of Wild Plant Parts on Growth and in the Control of Root Rot Fungi of Leguminous Crops

    International Nuclear Information System (INIS)

    Ikram, N.; Dawae, S.

    2016-01-01

    Present research work was carried out for the management of root rot fungi with wild plant part capsules and pellets formulation in soil. When application of pellets and capsules was carried out with Prosopis juliflora stem, leaves and flowers showed significant reduction in disease incidence and enhancement in growth and physiological parameters. Colonization of Fusarium spp., Macrophomina phaseolina and Rhizoctonia solani was completely suppressed when P. juliflora leaves pellets incorporated in soil. Physiological parameters such as chlorophyll a and b and protein were significantly increased when leaves pellets incorporated in soil at the rate of 1 percent w/w so P. juliflora leaves pellets were most effective in the control of root rot fungi and enhanced the growth of crop plants. (author)

  18. Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes

    Science.gov (United States)

    Nawaz, Muhammad; Abbasi, Muhammad Waseem; Hisaindee, Soleiman; Zaki, Muhammad Javed; Abbas, Hira Fatima; Mengting, Hu; Ahmed, M. Arif

    2016-05-01

    We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica.

  19. Role of mungbean root nodule associated fluorescent Pseudomonas and rhizobia in suppressing the root rotting fungi and root knot nematodes in chickpea (Cicer arietinum L.)

    International Nuclear Information System (INIS)

    Noreen, R.; Shafique, A.; Haque, S.E.; Ali, S.A.

    2016-01-01

    Three isolates each of fluorescent Pseudomonas (NAFP-19, NAFP-31 and NAFP-32) and rhizobia (NFB- 103, NFB-107 and NFB-109) which were originally isolated from root nodules of mungbean (Vigna radiata) showed significant biocontrol activity in the screen house and under field condition, against root rotting fungi viz., Macrophomina phaseolina, Fusarium solani, F. oxysporum and Rhizoctonia solani evaluated on chickpea. Biocontrol potential of these isolates was also evaluated against Meloidogyne incognita, the root knot nematode. Application of Pseudomonas and rhizobial isolates as a soil drench, separately or mixed significantly reduced root rot disease under screen house and field conditions. Nematode penetration in roots was also found significantly less in rhizobia or Pseudomonas treatments used separately or mixed as compared to control. Fluorescent Pseudomonas treated plants produced greater number of nodules per plant than control plants and about equal to rhizobia treated plants, indicating that root nodule associated fluorescent Pseudomonas enhance root nodulation. (author)

  20. Comparative efficacy of a red alga solieria robusta, chemical fertilizers and pesticides in managing the root diseases and growth of soybean

    International Nuclear Information System (INIS)

    Sultana, V.; Haque, S.E.; Baloch, G.N.; Ara, J.

    2011-01-01

    Application of seaweed as soil amendment for the control of soil borne plant diseases has increased in recent years due to their environment friendly role. In screen house study, a red seaweed Solieria robusta used as soil amendment showed better suppressive effect on root rotting fungus Fusarium solani than Topsin-M, a fungicide, but was found less effective than Topsin-M against Macrophomina phaseolina and Rhizoctonia solani on soybean. Solieria robusta showed similar suppressive effect on root knot nematode as did carbofuran, a nematicide. Seaweed showed slightly better effect on plant growth than urea or potash by producing taller plants, better root length and number of flowers per plant. However, mixed application of S.robusta and Topsin-M produced greater number of flowers per plant and tallest plants. (author)

  1. Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes.

    Science.gov (United States)

    Nawaz, Muhammad; Abbasi, Muhammad Waseem; Hisaindee, Soleiman; Zaki, Muhammad Javed; Abbas, Hira Fatima; Mengting, Hu; Ahmed, M Arif

    2016-05-15

    We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Study of homeopathic drugs on seed germination and fungal growth

    International Nuclear Information System (INIS)

    Hanif, A.; Dawar, S.

    2016-01-01

    In vitro, seeds of mungbean, sunflower, okra and mashbean were treated with homeopathic drugs namely Arnica montana and Thuja occidentalis (30C) were evaluated against root rot fungi. Different concentrations like 100, 75 and 50% v/v were tested to investigate seeds germination and inhibition of root rot fungi such as Fusarium oxysporum, Rhizoctonia solani and Macrophomina phaseolina. Results indicated that treated seeds of mungbean, sunflower, okra and mashbean with pure homeopathic drugs (100% v/v) by A. montana and T. occidentalis (30C) showed complete germination (100%), greater root length and excellent inhibition of root infecting pathogens. However, tested seeds treated with 75 and 50% v/v concentrations (prepared from 30C) by homeopathic drugs, respectively recorded significant increase in germination, root length and maximum zone of inhibition. (author)

  3. A Survey of Phytopathogenic Fungi and Oomycetes in Riyadh, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Arya Widyawan

    2015-06-01

    Full Text Available A survey of phytopathogenic fungi and Oomyceteswas conducted in Riyadh, Kingdom of Saudi Arabia duringOctober 2008 – May 2009. Total of 223 samples were collectedfrom four regions; Al-Kharj, Oyaynah, Old Diriyah, and Al Amariyah. Isolation was done using Potato Dextrose Agar(PDA. Infected parts were cut then sterilized in chlorox(10%, then were put in petridish that contain PDA andincubated at 25-27 °C. A total twelve genera of fungi andsingle genera of Oomycetes were isolated from the infectedplants and identifi ed as Fusarium spp., Alternaria spp.,Helmintosphorium (Bipolaris spp., Sclerotium spp., Rhizoctoniaspp., Cladosporium spp., Mauginiella scattae, Erysiphe spp.,Leveillula spp., Macrophomina phaseolina, Ustilago spp.,Ulocladium spp., and Phytium spp.

  4. Effects of cell suspension and cell·free culture filtrate of Pseudomonas aeruginosa in the control of root rot-root kont disease complex of tomato (Lycopersicon esculentum Mill.

    Directory of Open Access Journals (Sweden)

    I. A. Siddiqui

    2013-12-01

    Full Text Available The plant growth-promoting rhizobacterium Pseudomonas aeruginosa strain IE-6 was tested for antagonistic activity towards Meloidogyne javanica, the root-knot nematode and soilbome root-infecting fungi viz., Macrophomina phaseolina, Fusarium solani and Rhizoctonia solani under laboratory and greenhouse conditions. Cell-free culture filtrate of the bacterium caused significant reduction in egg hatching of M.javanica and inhibited radial growth of fungi in vitro. Cell-free culture filtrate also caused lyses in mycelium of F.solani. Under greenhouse conditions, soil drenches with the aqueous cell suspension or cell-free culture resulted in a considerable reduction in nematode population densities in soil and subsequent root-knot development due to M.javanica. In addition to nematode control, rhizobacterium application also inhibited root-infection caused by soilborne root~infecting fungi with significant enhancement of growth of tomato seedlings.

  5. Antifungal and phytotoxic activity of essential oil from root of Senecio amplexicaulis Kunth. (Asteraceae) growing wild in high altitude-Himalayan region.

    Science.gov (United States)

    Singh, Rajendra; Ahluwalia, Vivek; Singh, Pratap; Kumar, Naresh; Prakash Sati, Om; Sati, Nitin

    2016-08-01

    This work was aimed to evaluate the essential oil from root of medicinally important plant Senecio amplexicaulis for chemical composition, antifungal and phytotoxic activity. The chemical composition analysed by GC/GC-MS showed the presence of monoterpene hydrocarbons in high percentage with marker compounds as α-phellandrene (48.57%), o-cymene (16.80%) and β-ocimene (7.61%). The essential oil exhibited significant antifungal activity against five phytopathogenic fungi, Sclerotium rolfsii, Macrophomina phaseolina, Rhizoctonia solani, Pythium debaryanum and Fusarium oxysporum. The oil demonstrated remarkable phytotoxic activity in tested concentration and significant reduction in seed germination percentage of Phalaris minor and Triticum aestivum at higher concentrations. The roots essential oil showed high yield for one of its marker compound (α-phellandrene) which makes it important natural source of this compound.

  6. Trigonella foenum-graecum (fenugreek-mediated suppression of Meloidogyne javanica in mungbean

    Directory of Open Access Journals (Sweden)

    Tayyaba Zia

    2013-12-01

    Full Text Available Soil amendments with powdered seeds of Trigonella foenum - graecum (fenugreek caused soil suppressiveness against Meloidogyne javanica. Decomposed seeds of fenugreek caused marked reduction in nematode population densities and subsequent root-knot development as compared to the aqueous extract of the seeds indicating that some indirect factors are involved in the suppression of root-knot nematode. Both decomposed seeds and aqueous extracts enhanced plant height and fresh weights of shoot whereas root growth remained uninfluenced. Changes in fungal communities associated with nematode control were studied by comparing population numbers of fungi in the soil and in internal root tissues (endorhiza in non-amended and fenugreekamended soils. Acremonium sp., Chaetomium globosum, Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani were found to colonize inner root tissues of mungbean. Acremonium sp., C. globosum and F.solani were isolated in a relatively higher frequency from roots growing in the amended soils while M. phaseolina and R. solani colonized greatly in roots growing in non-amended soil. Of the fungi isolated from soils, Penicillium brefaldianum caused maximum juvenile mortality of M.javanica whereas F.solani caused greatest inhibition of egg hatch.

  7. Antifungal activity of methanolic extracts of some indigenous plants against common soil-borne fungi

    International Nuclear Information System (INIS)

    Tuba, T.; Abid, M.; Shaukat, S. S.; Shaikh, A.

    2016-01-01

    Present study was conducted to evaluate the fungicidal property of methanolic extracts of some indigenous plants of Karachi such as Hibiscus rosa-sinensis (leaves), The spesia populnea (leaves, stem and fruit), Withania somnifera (leaves and stem), Solanum surattense (shoot) and Melia azedarach (fruit) against common soil-borne phytopathogens viz., Macrophomina phaseolina, Rhizoctonia solani and Fusarium oxysporum by using food poison technique. Among the eight methanolic extracts of tested parts of plants, seven showed antifungal activity, of which T. populnea leaves and S. surattense shoots inhibited growth of all three test pathogens. Leaves of H. rosa-sinensis did not exhibit antifungal activity. T. populnea (leaves and stem), W. somnifera (stem) and M. azedarach (fruit) suppressed growth of Rhizoctonia solani by 100 percent. T. populnea leaves and M. azedarach fruit inhibited growth of M. phaseolina by 100 percent and 82 percent, respectively T. populnea leaves inhibited 99 percent mycelial growth of F. oxysporum. It is concluded that the methanolic extracts of the tested indigenous plants contain natural fungicidal compounds, which can be used for the control of common soil-borne pathogens. (author)

  8. Occurrence of Root Rot and Vascular Wilt Diseases in Roselle (Hibiscus sabdariffa L.) in Upper Egypt

    Science.gov (United States)

    Hassan, Naglaa; Shimizu, Masafumi

    2014-01-01

    Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt. PMID:24808737

  9. Occurrence of Root Rot and Vascular Wilt Diseases in Roselle (Hibiscus sabdariffa L.) in Upper Egypt.

    Science.gov (United States)

    Hassan, Naglaa; Shimizu, Masafumi; Hyakumachi, Mitsuro

    2014-03-01

    Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt.

  10. New insights in Trichoderma harzianum antagonism of fungal plant pathogens by secreted protein analysis.

    Science.gov (United States)

    Monteiro, Valdirene Neves; do Nascimento Silva, Roberto; Steindorff, Andrei Stecca; Costa, Fabio Teles; Noronha, Eliane Ferreira; Ricart, Carlos André Ornelas; de Sousa, Marcelo Valle; Vainstein, Marilene Henning; Ulhoa, Cirano José

    2010-10-01

    Trichoderma harzianum ALL42 were capable of overgrowing and degrading Rhizoctonia solani and Macrophomina phaseolina mycelia, coiling around the hyphae with formation of apressoria and hook-like structures. Hyphae of T. harzianum ALL42 did not show any coiling around Fusarium sp. hyphae suggesting that mycoparasitism may be different among the plant pathogens. In this study, a secretome analysis was used to identify some extracellular proteins secreted by T. harzianum ALL42 after growth on cell wall of M. phaseolina, Fusarium sp., and R. solani. The secreted proteins were analyzed by two-dimensional electrophoresis and MALDI-TOF mass spectrometry. A total of 60 T. harzianum ALL42 secreted proteins excised from the gel were analyzed from the three growth conditions. While seven cell wall-induced proteins were identified, more than 53 proteins spots remain unidentified, indicating that these proteins are either novel proteins or proteins that have not yet been sequenced. Endochitinase, β-glucosidase, α-mannosidase, acid phosphatase, α-1,3-glucanase, and proteases were identified in the gel and also detected in the supernatant of culture.

  11. In vitro antagonism of cotton seedlings fungi and characterization of chitinase isozyme activities in Trichoderma harzianum.

    Science.gov (United States)

    Asran-Amal, A; Moustafa-Mahmoud, S M; Sabet, K K; El Banna, O H

    2010-04-01

    The antagonistic fungus Trichoderma harzianum is widely recognized as a potential biocontrol agent against several soil-borne plant pathogens. T. harzinum is rich source of chitinoltic enzymes. In vitro screening of 5 isolates of T. harzinum, one isolate of Chaetomium globosum and one isolate of Conetherium mentance, revealed that all of them had reduced growth area of Macrophomina phaseolina, Fusarium solani and Rhizoctonia solani on PDA medium, significantly. The inhibition percentage ranged from 77.9 % to 55.9% for M. phaseolina and 59.2% to 40.4% for R. solani by T. harzinum and C. mentance, respectively. Inhibition for F. solani ranged from 76.5% to 55.7% by T. harzinum and C. globosum, respectively. Isozyme gel electrophoresis was used to assess chitinase activity secreted by selected isolates of T. harzinum under different pH degrees and temperatures. Obtained results indicated that activity of chitinase isozyme produced at 30 °C was higher than 15-20 °C for all tested isolates and activity of chitinase produced by isolates No. 4 and 5 of T. harzinum at pH (7-7.5) was higher than at pH 6, respectively.

  12. Survival of pathogens on soybean debris under no-tillage and conventional tillage systems Sobrevivência de patógenos em restos de cultura de soja mantidos em sistema de semeadura direta e convencional

    Directory of Open Access Journals (Sweden)

    Álvaro Manuel Rodrigues Almeida

    2001-10-01

    Full Text Available A study was conducted in the subtropical area of Southern Brazil to determine the survival of pathogens in soybean residues under conventional and no-tillage cultivation systems from March to September of 1998 and 1999. The pathogens most frequently isolated were Colletotrichum truncatum, Phomopsis spp., Cercospora kikuchii, Fusarium spp., Macrophomina phaseolina, and Rhizoctonia solani. Other fungi isolated were Myrothecium roridum, Penicillium sp., Chaetomium sp., Epicoccum sp., Corynespora cassiicola and Trichoderma sp. The percent of survival of each pathogen varied according to the month and the year. Survival of C. truncatum, Phomopsis spp. and C. kikuchii were significantly reduced (pAvaliou-se a sobrevivência de patógenos em restos de soja, em sistema de semeadura direta e convencional, entre março e setembro de 1998 e 1999, em Londrina, PR. Os patógenos mais freqüentemente isolados foram Colletotrichum truncatum, Phomopsis spp., Cercospora kikuchii, Fusarium spp., Macrophomina phaseolina e Rhizoctonia solani. Outros fungos isolados foram Myrothecium roridum, Penicillium sp., Chaetomium sp., Epicoccum sp., Corynespora cassiicola e Trichoderma sp. A porcentagem de sobrevivência variou com o mês e o ano. A sobrevivência de C. truncatum, Phomopsis spp. e C. kikuchii foi significativamente reduzida (P<0,05 entre a primeira e última avaliação nos resíduos mantidos sobre ou sob o solo. M. phaseolina e Fusarium spp. não foram afetados, ou foram favorecidos pelo enterro dos resíduos. A freqüência de isolamento de Fusarium spp. aumentou em resíduos enterrados no solo. A perda de biomassa mostrou redução de 44,4% no sistema convencional e 34,9% no sistema de semeadura direta, em 1998, quando a distribuição de chuvas foi mais regular. Em 1999, a redução foi de 48,2% e 39,0% para os sistemas convencional e de semeadura direta, respectivamente.

  13. Caracterización molecular y agronómica de aislados de Trichoderma spp nativos del noreste de México

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    José Luis Hernández Mendoza

    2011-07-01

    Full Text Available Título en ingles: Molecular and agronomic characterization of Trichoderma spp natives of northeastern Mexico  Resumen Trichoderma sp es un hongo frecuentemente usado en actividades agrícolas, pues actúa como antagonista de diversas especies de hongos fitopatógenos. En este estudio se realizó el aislamiento de cuatro cepas de Trichoderma sp nativas del noreste de México, las cuales fueron identificadas a nivel molecular mediante la secuenciación del ITS 1. Además se evaluó su capacidad antagonista en contra los hongos fitopatógenos Macrophomina phaseolina y Fusarium oxysporum, que afectan severamente cultivos de sorgo, maíz y fríjol en el noreste de México. La identificación se realizó de acuerdo al grado de concordancia con secuencias reportadas y corresponden a las especies T. hammatum (HK701;  T. koningiopsis (HK702; T. asperellum (HK703 y Trichoderma sp (HK704. Por otra parte, las pruebas de antagonismo muestran que los aislados HK701, HK703 y HK704 inhiben por competencia el crecimiento de M. phaseolina y F. oxysporum, mientras que HK702 tiene la capacidad para hiperparasitar dichos fitopatógenos. Finalmente, se evaluó la promoción de crecimiento de T. asperellum HK703, en maíz (Pionner 30P49®, usando para ello concentraciones de tratamiento de 1x10e2 hasta 1x10e6 esp/mL. En estos ensayos se midió la producción de biomasa. Los resultados muestran que en concentraciones intermedias se tiene el mayor incremento en altura de plantas y mayor producción de peso seco en follaje y raíz. Entre los parámetros antes mencionados existen diferencias significativas. Palabras clave: control biológico, antagonismo, biofertilizantes, Zea maiz, Sorghum bicolor. Abstract Trichoderma sp is a fungus often used in agricultural activities, because it acts as an antagonist of several species of plant pathogenic fungi. In this study four strains of Trichoderma sp was isolated from the northeastern Mexico, which were identified by

  14. Impact of management strategies in the basal rot, charcoal rots epidemiology and Phaseolus vulgaris L. yield.

    Directory of Open Access Journals (Sweden)

    Ulacio Osorio Dilcia

    2013-02-01

    Full Text Available The effect of chemical, physical, biologycal and cultural strategies individually or combinated were evaluated in the epidemiology of the basal rot (Sclerotium rolfsii, charcoal rot (Macrophomina phaseolina and the Phaseolus vulgaris cv Tacarigua yield at Barinas state from Venezuela. In the experiment, Tebuconazole (Teb was applicated at seed (1 L/Ton and at soil, a los 30 y 60 days after of the sow (1 L/ha; Trichoderma harzianum (Tri was applicated at seed (15 g for each 1.5 k and to 15, 30, 45 y 60 days after of the sow (30 g/10 L of water. On the other hand, soil was solarizated (Sol during 15 days and calcium nitrate (Ca (60 g/10 L of water was applicated each 15 days until 60 days of growth of cultivated plants. Basal rot was registered as far as 42 days after of the sow, showing less of 5.3% in Teb y the combination SolTeb. The hightest incidence of this disease was observed in the treatment Tri with 28.5%, being highter that control (14.5%. Last to 42 days predominated the charcoal rot in the rest of the plants for a total of 100% of incidente in everything the treatments. Nevertheless, Teb showed the hightest yield with 555 k/ha, being different estatistically at treatment TriCa, which showed the lowest yield with 31 k/ha, however, the roots not formed nodules nitrogen uptake in these replications with the fungicide and Ca. It is concluded that S. rolfsii was sensible at action of some of the treatments; but not M. phaseolina; nevertheless, the plants were capables to produce seeds health apparently in treatments in which observed less severity of charcoal rot.

  15. Combined effects of biocontrol agents and soil amendments on soil microbial populations, plant growth and incidence of charcoal rot of cowpea and wilt of cumin

    Directory of Open Access Journals (Sweden)

    Vijeta SINGH

    2012-09-01

    Full Text Available Field experiments were conducted for 2 years to determine the effectiveness of combined use of two biocontrol agents, Bacillus firmus and Aspergillus versicolor for control of Macrophomina phaseolina induced charcoal rot of cowpea and Fusarium oxysporum f. sp. cumini induced wilt of cumin. The lowest level of plant mortality (3‒4% due to charcoal rot of cowpea was recorded when bacterium coated seeds were sown in radish compost amended soil compared to the non-amended soil (13.8‒20.5%, but this was not significantly better than some other treatments. Cowpea roots from B. firmus coated seeds had better nodulation than any of the individual A. versicolor treatments. Although B. firmus coated seeds + A. versicolor + farmyard manure resulted in maximum nodulation this was not significantly different to B. firmus seed coating. Root colonization by the combined biocontrol agent treatments was better than the individual biocontrol agent treatments. Combining A. versicolor with farmyard manure supported the maximum populations of total fungi and actinomycetes. In both winter seasons, the lowest incidence of wilt (1.0‒5.2% on cumin was recorded when A. versicolor was amended with neem compost compared to the non-amended soil (5.7‒10.5%. Maximum colonization of A. versicolor on roots was observed in B. firmus + A. versicolor + farmyard manure amended plots. During both years, the treatment combination of A. versicolor in neem compost amended plots resulted in maximum populations of fungi, bacteria and A. versicolor in the soil, which was greater than in the non-amended soil. Significant increases in disease control were not recorded after single or repeated delivery of A. versicolor. These results suggest that combining B. firmus as seed coatings with A. versicolor as soil applications gives improved control of M. phaseolina and Fusarium induced diseases on legume and seed spice crops in arid soils.

  16. Planting history and propagule pressure as predictors of invasions by woody species in a temperate region

    Czech Academy of Sciences Publication Activity Database

    Křivánek, Martin; Pyšek, Petr; Jarošík, Vojtěch

    2006-01-01

    Roč. 20, č. 5 (2006), s. 1487-1498 ISSN 0888-8892 R&D Projects: GA ČR GA206/03/1216 Institutional research plan: CEZ:AV0Z60050516 Keywords : alien forestry trees * invasive trees * naturalization Subject RIV: EF - Botanics Impact factor: 3.762, year: 2006

  17. Nonnative plant response to silvicultural treatments: A model based on disturbance, propagule pressure, and competitive abilities

    Science.gov (United States)

    Steve Sutherland; Cara R. Nelson

    2010-01-01

    Invasion by nonnative plants can result in substantial adverse effects on the functions of native forest ecosystems, including nutrient cycling and fire regimes. Thus, forest managers need to be aware of the potential impacts of management activities, including silvicultural treatments, on nonnative vegetation. To aid in that effort, we created a conceptual model of...

  18. Use of storage substance in garlic propagules irradiated of gamma rays

    International Nuclear Information System (INIS)

    Perez Talavera, S.; Lopez Cervantes, M.; Perez Lezcano, A.

    1997-01-01

    Gamma radioinduced effects on different growth indicators and the destination of storage substances of cloves were investigated in garlic cv. Martinez. To this purpose, the doses interval of its radiosensitivity curve was considered. Within the Gr 10-20 (growth reduction) interval there was no damage or if was small in growth indicators and also leaves width was stimulated, enabling to each leave areas similar to those of testing plants. In addition significant increases of storage compounds use in cloves were observed. This result may be interpreted as an additional energetic consumption to repair radiation damage. Behaviour starting at Gr 30 may be critical because plants undergo severe damage in most of the analyzed indicators principally those that depend of leaves area. This result. from a physiological point of view, complement the recommendation of selecting doses in Gr 10-20 interval for the radio mutagenesis works, recommendation made in base of small lethality and sterility, and high percentage of useful mutation reported for this doses interval

  19. [Physical and chemical methods for eliminating propagules of indigenous mycorrhizal fungi from soil samples].

    Science.gov (United States)

    Covacevich, Fernanda; Castellari, Claudia C; Echeverría, Hernán E

    2014-01-01

    The objective of this work was to evaluate methods to eliminate or reduce the number of indigenous arbuscular mycorrhizal fungi (AMF) from soil samples without affecting their edaphic or microbiological properties. At an early trial we evaluated moist heat (autoclaving), dry heat (oven), sodium hypochlorite (NaClO) and formaldehyde at a range of 100.0-3.3μl/g and 16.7-3.3μl/g respectively. There was no germination in plants of ryegrass (Lolium multiflorum Lam.) sown on substrates receiving NaClO (100.0-33.3μl/g), whereas autoclaving significantly increased the available soil phosphorous content. Both treatments failed to eradicate AMF colonization at 9 weeks; therefore, they were discarded. In a second trial, oven and formaldehyde (10.0μl/g) treatments were analyzed to assess the effects of seed decontamination and AMF reinoculation. Both procedures were effective in reducing or eliminating indigenous AMF at a range of soil P availability of 12-29mg/kg. However, the time between soil treatment and AMF multiplication and safety requirements were greater in the case of formaldehyde application. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España. All rights reserved.

  20. Temporal variation of diatom benthic propagules in a monsoon-influenced tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S.; Anil, A.C.

    .danLic.jeu Nav.(big)Nav.delNit.angNit.closNit.lonNit.panNit.serNit.sigPle.angSke.cos Sur.spTha.freThal.exc Thal.spp Thx.nit Stress: 0.01 Distance Ske.cos Frag.sp Tha spp Cha.cur Nav.del Nav.sp1 Amp.cof Ast.jap Nav.cru Nit.pan Bid.rho Nit.bil Tha.nit Nav.sp2 Nav... Bottom Centrics 1 Asteromphalus sp. Ast.sp 27 27 2 Bacteriastrum delicatulum Cleve Bac.del 53 3 Bacteriastrum fusus Bac.fus 27 4 Bacteriastrum hyalinum Lauder Bac.hya 533 347 5 Bacteriastrum varians Bac.var 27 6 Biddulphia granulata Bid.gra 3 7 Biddulphia...

  1. Naturalization of central European plants in North America: species traits, habitats, propagule pressure, residence time

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Manceur, A. M.; Alba, Christina; McGregor, Kirsty; Pergl, Jan; Štajerová, Kateřina; Chytrý, M.; Danihelka, Jiří; Kartesz, J.; Klimešová, Jitka; Lučanová, Magdalena; Moravcová, Lenka; Nishino, M.; Sádlo, Jiří; Suda, Jan; Tichý, L.; Kühn, I.

    2015-01-01

    Roč. 96, č. 3 (2015), s. 762-774 ISSN 0012-9658 R&D Projects: GA ČR GB14-36079G; GA ČR(CZ) GA14-15414S; GA ČR(CZ) GAP504/11/1028; GA ČR(CZ) GAP505/11/1112 Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : invasions * naturalization * species traits Subject RIV: EH - Ecology, Behaviour Impact factor: 4.733, year: 2015

  2. Evaluation of biocontrol potential of epiphytic fluorescent pseudomonas as associated with healthy fruits and vegetables against root rot and root knot pathogens of mungbean

    International Nuclear Information System (INIS)

    Habiba, A.; Noreen, R.; Ali, S. A.; Sultana, V.; Ara, J.

    2016-01-01

    Endophytic and rhizospheric fluorescent Pseudomonas have widely been used as biological control agents against soilborne plant pathogens. In this study, fifteen epiphytic fluorescent Pseudomonas isolated from the surfaces of citrus (grapefruit, orange and lemon) melon and tomato fruits were characterized for their in vitro activity against root rotting fungi viz., Macrophomina phaseolina, Fusarium solani, F. oxysporum and Rhizoctonia solani and nematicidal activity against the second stage juveniles of Meloidogyne javanica. Out of fifteen Pseudomonas isolates HAB-16, HAB-1 and HAB-25 inhibited the growth of all the test fungi and showed maximum nematicidal activity against second stage juvenile of M. javanica. Based on their effective in vitro activity nine epiphytic fluorescent Pseudomonas were evaluated for their growth promoting ability and biocontrol activity in screen house on mungbean. Pseudomonas isolates (HAB-13, HAB-2, HAB-4, HAB-1, HAB-14, HAB-9, HAB-7 and HAB-25) used as soil drench greatly reduced the root rot-root knot infection and thereby enhanced plant growth, root nodulation and yield in mungbean. Besides, rhizospheric and endophytic, epiphytic fluorescent Pseudomonas associated with healthy fruits may be used as biocontrol agent against root rotting fungi, besides, using for the mangemnet of postharvest diseases. (author)

  3. CUANTIFICACIÓN DE ENFERMEDADES EN LÍNEAS PROMISORIAS Y VARIEDADES DE FRÉJOL EN QUEVEDO, ECUADOR

    Directory of Open Access Journals (Sweden)

    FELIPE RAFAEL GARCÉS-FIALLOS

    Full Text Available El rendimiento del cultivo de fréjol (Phaseolus vulgaris L. es disminuido por el ataque de las enfermedades a lo largo del ciclo del cultivo, disminuyendo los ingresos de los agricultores en la zona central del Litoral Ecuatoriano. El objetivo de la investigación fue identificar cuales son las enfermedades que se presentan, y cuantificar las mismas en 21 materiales genéticos de fréjol en el cantón Quevedo. Se describieron los agentes causales de la muerte de plántulas luego de la emergencia, así como las enfermedades presentes en el agroecosistema de fréjol. También se cuantificó la severidad (% de enfermedades foliares en plantas y por parcela, roya (Uromyces appendiculatus, mustia hilachosa (Rhizoctonia solani, así como la incidencia (% de virosis y pudriciones radiculares. Fueron encontrados patógenos causantes de la muerte de plántulas (Fusarium spp., R. solani y Macrophomina phaseolina, enfermedades foliares predominantes (U. appendiculatus y R. solani, la presencia de virosis y finalmente los microorganismos promotores de pudriciones radiculares (fusariosis, pudrición de rhizoctonia y macrofomina. Fue evidenciado comportamiento diferenciado entre los cultivares evaluados. Los materiales que obtuvieron una menor intensidad de problemas fitosanitarios fueron el CAL - 96, EVG - 06 - 103, Cf4 0-0-4-8, INIAP-473 y Cf4 0-0-12-5

  4. Genome Sequencing of a Mung Bean Plant Growth Promoting Strain of P. aeruginosa with Biocontrol Ability

    Directory of Open Access Journals (Sweden)

    Devaraj Illakkiam

    2014-01-01

    Full Text Available Pseudomonas aeruginosa PGPR2 is a mung bean rhizosphere strain that produces secondary metabolites and hydrolytic enzymes contributing to excellent antifungal activity against Macrophomina phaseolina, one of the prevalent fungal pathogens of mung bean. Genome sequencing was performed using the Ion Torrent Personal Genome Machine generating 1,354,732 reads (6,772,433 sequenced bases achieving ~25-fold coverage of the genome. Reference genome assembly using MIRA 3.4.0 yielded 198 contigs. The draft genome of PGPR2 encoded 6803 open reading frames, of which 5314 were genes with predicted functions, 1489 were genes of known functions, and 80 were RNA-coding genes. Strain specific and core genes of P. aeruginosa PGPR2 that are relevant to rhizospheric habitat were identified by pangenome analysis. Genes involved in plant growth promoting function such as synthesis of ACC deaminase, indole-3-acetic acid, trehalose, mineral scavenging siderophores, hydrogen cyanide, chitinases, acyl homoserine lactones, acetoin, 2,3-butanediol, and phytases were identified. In addition, niche-specific genes such as phosphate solubilising 3-phytase, adhesins, pathway-specific transcriptional regulators, a diguanylate cyclase involved in cellulose synthesis, a receptor for ferrienterochelin, a DEAD/DEAH-box helicase involved in stress tolerance, chemotaxis/motility determinants, an HtpX protease, and enzymes involved in the production of a chromanone derivative with potent antifungal activity were identified.

  5. Antimicrobial activity screening of isolated flavonoids from Azadirachta indica leaves

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    QUDSIA KANWAL

    2011-03-01

    Full Text Available The antimicrobial activities of two flavonoids, namely genistein 7-O-glucoside (1 and (–-epi-catechin (2, isolated from Azadirachta indica A. Juss (neem leaves, were evaluated against five fungal species, viz: Alternaria alternata (Fr. Keissler, Aspergillus fumigatus Fresenius, Aspergillus niger van Tieghem, Macrophomina phaseolina (Tassi Goid. and Penicillium citrii, and four bacterial species, viz. Lactobacillus sp., Escherichia coli, Azospirillium lipoferum and Bacillus sp. Six concentrations, viz. 100, 300, 500, 700, 900 and 1000 ppm of each of the two flavonoids were employed using malt extract agar medium. All the concentrations of both the test compounds significantly suppressed fungal as well as bacterial growth. The highest concentration (1000 ppm of both fractions 1 and 2 reduced the growth of the different test fungal species by 83–99 % and 82–95 %, respectively. Compound 1 was highly effective against Lactobacillus sp., against which its various concentrations reduced the bacterial growth by 52–99.8 %. Compound 2 was highly effective against A. lipoferum and Bacillus sp., resulting in 94–100 % and 73–99% reduction in bacterial growth, respectively.

  6. Effect of agricultural inputs and essential oils on the soil of vegetables in Colombia's Caribbean region

    Directory of Open Access Journals (Sweden)

    Eduardo Mena-Rodríguez

    2018-01-01

    Full Text Available The contribution of vegetables to food security and economic development in Colombia, as well as to environmental problems worldwide, justifies the interest to design sustainable production strategies for the agro-chain. This study was developed to evaluate the effect of the application of essential oils and agricultural inputs in chili peppers, beans and eggplants in Codazzi, Cesar, Colombia. The methodology included the compatibility analysis between pesticides used in these vegetables, and Lippia alba and Cymbopogon citratus oils in relation to their biocidal effect in vitro on native strains of Macrophomina phaseolina, Phytophthora capsici and Colletotrichum gloeosporioides. Applications of thiabendazole in an individual basis and combined with oils were carried out in the field. Physicochemical and microbiological indicators of soil, pests and diseases incidence and crop yield were measured. Oils controlled up to 97% of plant pathogens in vitro and exhibited compatibility with carbendazim and thiabendazole. In the field, up to 67 % of disease control was observed with C. citratus + thiabendazole compared to the control (p = 0.00, yields were close to the regional average, and better microbiological and physicochemical soil conditions were observed. In conclusion, there are differences in the edaphic effect between treatments, as the agrochemical and the oil combinations were more favorable than the individual effect of each product on the variables evaluated. The above exhorts to continue soil evaluations with oils to elucidate the duration of the described effects.

  7. Genomic insights into the broad antifungal activity, plant-probiotic properties, and their regulation, in Pseudomonas donghuensis strain SVBP6

    Science.gov (United States)

    Iriarte, Andrés; Valverde, Claudio Fabián

    2018-01-01

    Plant-growth promotion has been linked to the Pseudomonas genus since the beginning of this research field. In this work, we mined the genome of an Argentinean isolate of the recently described species P. donghuensis. Strain SVBP6, isolated from bulk soil of an agricultural plot, showed a broad antifungal activity and several other plant-probiotic activities. As this species has been recently described, and it seems like some plant-growth promoting (PGP) traits do not belong to the classical pseudomonads toolbox, we decide to explore the SVBP6 genome via an bioinformatic approach. Genome inspection confirmed our previous in vitro results about genes involved in several probiotic activities. Other genetic traits possibly involved in survival of SVBP6 in highly competitive environments, such as rhizospheres, were found. Tn5 mutagenesis revealed that the antifungal activity against the soil pathogen Macrophomina phaseolina was dependent on a functional gacS gene, from the regulatory cascade Gac-Rsm, but it was not due to volatile compounds. Altogether, our genomic analyses and in vitro tests allowed the phylogenetic assignment and provided the first insights into probiotic properties of the first P. donghuensis isolate from the Americas. PMID:29538430

  8. Combined effect of soil amendment with oil cakes and seed priming in the control of root rot fungi of leguminous and non-leguminous crops

    International Nuclear Information System (INIS)

    Rafi, H.; Dawar, S.; Tariq, M.

    2016-01-01

    Organic amendments of soil help in proper aeration, rising of temperature and water holding capacity which results in better uptake of nutrients with root system gets extensive establishment. In this study, effects of soil amendment with oil seed cakes including mustard (Brassica campestris L.), cotton (Gossypium hirsutum L.), almond (Prunus amygdalus L.) and black seed (Nigella sativa L.) cakes at the rate of 0.1 and 1% w/w and priming of seeds with Acacia nilotica (L.) Willd. ex Delile and Sapindus mukorossi (L.) leaves extracts and microbial antagonists (Trichoderma harzianum and Rhizobium melilotii) was observed on the growth of plants and in the suppression of root infecting fungi. The results obtained showed that combined effect of bio-priming of seeds with T. harzianum spore suspension and amendment of soil with mustard cake at the rate of 1% was found to be most effective for the growth of leguminous and non-leguminous crop plants (peanut, chickpea, okra and sunflower) and for the reduction of root infecting fungi like Macrophomina phaseolina, Fusarium spp followed by R. meliloti primed seeds in combination with cotton, almond and black seed cakes amendment respectively as compared to control (non treated seeds and soil). (author)

  9. Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation.

    Science.gov (United States)

    Goel, Garima; Pandey, Piyush; Sood, Anchal; Bisht, Sandeep; Maheshwari, D K; Sharma, G D

    2012-06-01

    Rhizoremediation of organic xenobiotics is based on interactions between plants and their associated micro-organisms. The present work was designed to engineer a bacterial system having toluene degradation ability along with plant growth promoting characteristics for effective rhizoremediation. pWWO harboring the genes responsible for toluene breakdown was isolated from Pseudomonas putida MTCC 979 and successfully transformed in Rhizobium DPT. This resulted in a bacterial strain (DPT(T)) which had the ability to degrade toluene as well as enhance growth of host plant. The frequency of transformation was recorded 5.7 × 10(-6). DPT produced IAA, siderophore, chitinase, HCN, ACC deaminase, solubilized inorganic phosphate, fixed atmospheric nitrogen and inhibited the growth of Fusarium oxysporum and Macrophomina phaseolina in vitro. During pot assay, 50 ppm toluene in soil was found to inhibit the germination of Cajanus cajan seeds. However when the seeds bacterized with toluene degrading P. putida or R. leguminosarum DPT were sown in pots, again no germination was observed. Non-bacterized as well as bacterized seeds germinated successfully in toluene free soil as control. The results forced for an alternative mode of application of bacteria for rhizoremediation purpose. Hence bacterial suspension was mixed with soil having 50 ppm of toluene. Germination index in DPT treated soil was 100% while in P. putida it was 50%. Untreated soil with toluene restricted the seeds to germinate.

  10. Tandem mass spectrometry approach for the investigation of the steroidal metabolism: structure-fragmentation relationship (SFR) in anabolic steroids and their metabolites by ESI-MS/MS analysis.

    Science.gov (United States)

    Musharraf, Syed Ghulam; Ali, Arslan; Khan, Naik Tameem; Yousuf, Maria; Choudhary, Muhammad Iqbal; Atta-ur-Rahman

    2013-02-01

    Electrospray ionization tandem mass spectrometry (ESI-MS/MS) was used to investigate the effect of different substitutions introduced during metabolism on fragmentation patterns of four anabolic steroids including methyltestosterone, methandrostenolone, cis-androsterone and adrenosterone, along with their metabolites. Collision-induced dissociation (CID) analysis was performed to correlate the major product ions of 19 steroids with structural features. The analysis is done to portray metabolic alteration, such as incorporation or reduction of double bonds, hydroxylations, and/or oxidation of hydroxyl moieties to keto functional group on steroidal skeleton which leads to drastically changed product ion spectra from the respective classes of steroids, therefore, making them difficult to identify. The comparative ESI-MS/MS study also revealed some characteristic peaks to differentiate different steroidal metabolites and can be useful for the unambiguous identification of anabolic steroids in biological fluid. Moreover, LC-ESI-MS/MS analysis of fermented extract of methyltestosterone, obtained by Macrophomina phaseolina was also investigated. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Control of Root Rot and Wilt Diseases of Roselle under Field Conditions

    Science.gov (United States)

    Hassan, Naglaa; Elsharkawy, Mohsen Mohamed; Shimizu, Masafumi

    2014-01-01

    Roselle (Hibiscus sabdariffa L.) is one of the most important medicinal crops in many parts of the world. In this study, the effects of microelements, antioxidants, and bioagents on Fusarium oxysporum, F. solani, and Macrophomina phaseolina, the causal pathogens of root rot and wilt diseases in roselle, were examined under field conditions. Preliminary studies were carried out in vitro in order to select the most effective members to be used in field control trials. Our results showed that microelements (copper and manganese), antioxidants (salicylic acid, ascorbic acid, and EDTA), a fungicide (Dithane M45) and biological control agents (Trichoderma harzianum and Bacillus subtilis) were significantly reduced the linear growth of the causal pathogens. Additionally, application of the previous microelements, antioxidants, a fungicide and biological control agents significantly reduced disease incidence of root rot and wilt diseases under field conditions. Copper, salicylic acid, and T. harzianum showed the best results in this respect. In conclusion, microelements, antioxidants, and biocontrol agents could be used as alternative strategies to fungicides for controlling root rot and wilt diseases in roselle. PMID:25606010

  12. Control of some important soil-borne fungi by chitin associated with chilli (capsicum annuum l.) in lower sindh, pakistan

    International Nuclear Information System (INIS)

    Hussain, F.; Abid, M.; Farzana, A.; Akbar, M.; Shaukat, S.S.

    2013-01-01

    Chilli (Capsicum annuum L.) belongs to the family Solanaceae is one of the most important cash crop of the southern parts of Pakistan. Capsicum is cultivated on a large scale in a lower region of Sindh, Pakistan. It is an important and profitable crop of Pakistan. Several biotic and abiotic stresses affect the productivity of chilli crop. It is infected by a number of diseases particularly soil-borne diseases. Surveys of soil-borne fungal diseases associated with chilli crop in different areas of lower Sindh, including, Hyderabad, Tando Allahyar, Mirpurkhas, Umerkot, Kunri, Samaro, Kot Ghulam uhammad and Digri, were conducted, and chilli plants showing symptoms of wilting were collected. A number of soil-borne root infecting fungi were isolated and identified, such as, Fusarium oxysporum, F. solani, Macrophomina phaseolina, Phytophthora capsici, Pythium sp., and Rhizoctonia solani, from collected disease plants. It was observed that all the major varieties of chillies (i.e., Sanam, Talhari, Ghotaki, Mexi), growing in lower Sindh, were highly susceptible to these fungi. The main objectives of the study were to examine the effectiveness of chitin for the management of soil-borne diseases of chilli plant by different methods, i.e., soil amendment and transplant root dip method. Results indicated that of the two methods, the soil amendment method was more effective while transplant root dip method was less effective. (author)

  13. Root rot diseases of sugarbeet (Beta vulgaris L as affected by defloliation intensity

    Directory of Open Access Journals (Sweden)

    Karadimos Dimitros A.

    2006-01-01

    Full Text Available The aim of this work was to study the effect of sugar beet re-growth after water stress defoliation on root rots of three cultivars (Europa, Rival Corsica, which were spring sown in Thessaly, central Greece, for two growing seasons (2003-04. At the beginning of July, sugar beets were subjected to water deficit with irrigation withholding. A month later, three defoliation levels (control - C, moderate - MD, severe - SD and irrigation were applied. Thus, sugar beets were forced to re-grow and three harvests (15, 30 and 40 days after defoliation - DAD were conducted. Rotted roots per hectare were counted and pathogens were identified. Data were analyzed as a four-factor randomized complete block design with years, defoliation levels, sampling times and cultivars as main factors. The number of rotted roots was increased with the defoliation level and was significantly higher for SD sugar beets (3748 roots ha–1. No significant differences were found between C and MD treatments (1543 and 2116 roots ha–1, respectively. Rival was the most susceptible cultivar to root rots. Sugar beets were more susceptible to rotting 15 and 40 DAD (2778 and 2998 roots ha–1. The causal agents of root rots were the fungi, Fusarium spp., Rhizopus stolonifer, Macrophomina phaseolina and Rhizoctonia solani.

  14. Seed priming with extracts of Acacia nilotica (L.) Willd. ex Delile and Sapindus mukorossi (L.) plant parts in the control of root rot fungi and growth of plants

    International Nuclear Information System (INIS)

    Rafi, H.; Dawar, S.; Zaki, M.J.

    2015-01-01

    Seed priming with plant extracts and chemicals has been used as an important growth enhancement tool in crop plants. In this research, an attempt was made to understand the mechanism of various seed priming treatments on greenhouse-grown okra (Abelmoschus esculentus (L.) Moench.), sunflower (Helianthus annuus L.), peanut (Arachis hypogaea L.) and chickpea (Cicer arietinum L.) for the control of root infecting fungi like Rhizoctonia solani (Kn), Fusarium spp. and Macrophomina phaseolina (Tassi) Goid by plant parts extracts (stem, leaves and seeds) of Acacia nilotica (L.) Willd. ex Delile and Sapindus mukorossi (L) at different time intervals (5, 10, 20, 40 minutes). Results showed significant suppression of root rot fungi and significantly enhanced the growth parameters like shoot length, root length, shoot weight and root weight. Seed-priming with A. nilotica and S. mukorossi leaves extract for 10 minutes time interval was found to be effective for the control of root rot fungi and growth of all tested leguminous and non-leguminous plants. (author)

  15. Effect of endophytic pseudomonas aeruinosa and trichoderma harzianum on soil-borne diseases, mycorrhizae and induction of systemic resistance in okra grown in soil amended with vernonia anthelmintica (L.) seeds powder

    International Nuclear Information System (INIS)

    Shafique, H. A.; Noreen, R.; Haque, S. E. U.; Sultana, V.; Ara, J.

    2015-01-01

    Biostimulants are used in agricultural practices for plant growth improvement. These fertilizers improve microbial activity and cause a negative impact on soil-borne pathogens. In recent years, stimulating plant natural defense is considered as most promising alternative strategy for crop productivity. The present study was carried out to examine the effect of endophytic Pseudomonas aeruginosa and Trichoderma harzianum in soil amendment with Vernonia anthelmintica seeds powder, on root rotting fungi, plant growth, mycorrhizal population around roots, phosphorous uptake and stimulation of plant defense markers like poylphenol and antioxidant status in okra. Combine application of Vernonia with Pseudomonas aeruginosa and Trichoderma harzianum significantly (p<0.05) suppressed Rhizoctonia solani and Fusarium oxysporum with complete reduction of Macrophomina phaseolina and Fusarium solani. Pseudomonas aeruginosa and T. harzianum alone or in Vernonia amended soil significantly reduced nematode galls on roots. Organic amendment also improved plant resistance against root diseases as evident from enhanced DPPH radical scavenging capacity and polyphenol content in treated plants as compare to control. VA Mycorrhizal spores were found significantly (p<0.05) higher in number around roots received Pseudomonas aeruginosa or T. harzianum alone or in Vernonia amended soil. Whereas, higher concentrations of phosphorus in okra shoots were found in plants received biocontrol agents in amended soil. Mixed application of PGPR and T. harzianum in amended soil produced tallest plants than other treatments. Soil amendment with Vernonia seed powder alone or with biocontrol agents offer a non-chemical means of plant disease control. (author)

  16. QUALIDADE FISIOLÓGICA E INCIDÊNCIA DE FUNGOS EM SEMENTES DE FEIJÃO CAUPI PRODUZIDAS DO ESTADO DO CEARÁ

    Directory of Open Access Journals (Sweden)

    Delineide Pereira Gomes

    2008-01-01

    Full Text Available This work had the purpose evaluate physiological quality and incidence of fungi in twelve cowpea seeds cultivars, produced in the state of Ceará, Brazil, in 2005. The physiological quality was evaluated through the germination standard and vigour tests (First germination count and sanity quality was evaluated through the method paper filter (blotter test being used four repetitions of 100 seeds. In relation physiological potential of cultivars, it was observed that the cultivars presented low vigour, like Galanjão (0 %, Costela de Vaca (11,49 % and Parambú (16,6 %. The germination index were low too, except Sempre Verde with 70,33 % the germination of seedlings normal. In respect the incidence of fungi in the seeds, the Fusarium spp. was detected in 0,5 a 0,6 %, Colletotrichum only in Corujinha (0,5 %, Pingo de Ouro 3 (2 % and Macrophomina phaseolina was detected only in Costela de vaca and Pingo de ouro (0,5 % and Galanjão (7 %. The incidence of Aspergillus spp. was verified in all you cultivars and Penicillium sp. was detected only in Galanjão, Pingo de Ouro and Costela de Vaca (12 %. Others fungi like Curvularia sp., Phoma sp., Trichoderma sp. and Alternaria sp. were detected in low incidence. The seeds evaluated shown a low physiological quality and the most frequent fungi were those of storage.

  17. Effects of different irrigation methods on pepper yield and soilborne diseases incidence

    Directory of Open Access Journals (Sweden)

    Seral YÜCEL

    2013-12-01

    Full Text Available In this study, the effect of different irrigation strategies and irrigation methods on yields and the incidence of wilt (Fusarium oxysporum and root rot (Fusarium solani and Macrophomina phaseolina diseases causing significant yield losses on field grown processing red pepper is determined. Experiments were carried out at Topçu Station of the Soil and Water Resources Research Institute of Tarsus in 2010 and 2011. Karaisalı processing pepper (Capsicum annuum L. was used in the experiments. Three furrows and five drip irrigation treatments were used in the study. The disease incidence rates were found 8.0-18.2% in furrow irrigation plots and 4.5-10.0% in drip irrigation plots in 2010, while it was 3.4-9.7% in furrow irrigation plots and 2.2-4.5% in drip irrigation plots in 2011. Pepper yields ranged from 3 416 to 4 417 kg da-1 and 3 376 to 4 779 kg da-1 in drip irrigated plots in 2010 and 2011, respectively. However, yields varied between 3 172-3 559 kg da-1 and 2 932-4 150 kg da-1 in furrow irrigated plots in 2010 and 2011 growing seasons.

  18. Incorporation of plant materials in the control of root pathogens in muskmelon

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    Andréa Mirne de Macêdo Dantas

    2013-12-01

    Full Text Available The effect of plant materials[Sunn Hemp (Crotalaria juncea, Castor Bean (Ricinus communis L., Cassava (Manihot esculenta Crantz and Neem (Azadirachta indica] and the times of incorporation of these materials in regards to the incidence of root rot in melon was evaluated in Ceará state, Brazil. The experiment was conducted in a commercial area with a history of root pathogens in cucurbitaceae. The randomized block design was used, in a 5 x 3 factorial arrangement with four repetitions. The treatments consisted of a combination of four plant materials (sunn hemp, castor beans, cassava and neem and a control with no soil incorporation of plant material and three times of incorporation (28, 21, and 14 days before the transplanting of the seedlings. Lower incidence of root rot was observed in practically all of the treatments where materials were incorporated at different times, with variation between the materials, corresponding with the time of incorporation, in relation to the soil without plant material. The pathogens isolated from the symptomatic muskmelon plants were Fusarium solani, Macrophomina phaseolina, Monosporascus cannonballus and Rhizoctonia solani, F. solani being encountered most frequently.

  19. Integrated approach for disease management and growth enhancement of Sesamum indicum L. utilizing Azotobacter chroococcum TRA2 and chemical fertilizer.

    Science.gov (United States)

    Maheshwari, D K; Dubey, R C; Aeron, Abhinav; Kumar, Bhavesh; Kumar, Sandeep; Tewari, Sakshi; Arora, Naveen Kumar

    2012-10-01

    Azotobacter chroococcum TRA2, an isolate of wheat rhizosphere displayed plant growth promoting attributes including indole acetic acid, HCN, siderophore production, solubilization of inorganic phosphate and fixation of atmospheric nitrogen. In addition, it showed strong antagonistic effect against Macrophomina phaseolina and Fusarium oxysporum. It also caused degradation and digestion of cell wall components, resulting in hyphal perforations, empty cell (halo) formation, shrinking and lysis of fungal mycelia along with significant degeneration of conidia. Fertilizer adaptive variant strain of A. chroococcum TRA2 was studied with Tn5 induced streptomycin resistant transconjugants of wild type tetracycline-resistant TRA2 (designated TRA2(tetra+strep+)) after different durations. The strain was significantly competent in rhizosphere, as its population increased by 15.29 % in rhizosphere of Sesamum indicum. Seed bacterization with the strain TRA2 resulted in significant increase in vegetative growth parameters and yield of sesame over the non-bacterized seeds. However, application of TRA2 with half dose of fertilizers showed sesame yield almost similar to that obtained by full dose treatment. Moreover, the oil yield increased by 24.20 %, while protein yield increased by 35.92 % in treatment receiving half dose of fertilizer along with TRA2 bacterized seeds, as compared to untreated control.

  20. Soil borne gungi associated with different vegetable crop in sindh, pakistan

    International Nuclear Information System (INIS)

    Usman, F.; Abid, M.; Hussain, F.

    2014-01-01

    Different soil-borne fungi are responsible for reducing the yield of vegetables throughout the world including Pakistan. There are several soil borne fungal pathogens which aggressively infect vegetable crops. Surveys conducted during September 2010 to October 2011, demonstrated that a great diversity of soil borne plant pathogens associated with different vegetables prevail in vegetable growing areas of Sindh such as Tando Allahayar, Mirpurkhas, Ghotaki, Khairpur, Kunri, Umerkot and Karachi, etc. Our study noted in total thirteen different genera of fungi isolated from vegetable crops (cabbage, brinjal, tomato, radish and spinach). Isolated fungi identified included Alternaria solani, Aspergillus flavus, A. fumigatus, A. niger, A. oryzae, A. terrus, Aeromonium fusidiocles, Cladosporium sp., Drechselra hawaiiensis, Eurotium berbanbrum, Fusarium oxysporum, Macrophomina phaseolina, Penicillium commune, Rhizoctonia solani, Trichoderma harzianum, Ulocladium sp., and unidentified black mycelium from the soil and roots of vegetable crops. In addition, it was found that soil is commonly infected by soil-borne fungi and eventually results in heavy losses of vegetable yield in the vegetable growing areas of Sindh province. The infection rapidly increased due to many factors such as, presence of moisture, excess of water and infection may be caused by winds, gales and dust storms as well as by mechanical vectors. (author)

  1. Efeito de lodo de esgoto sobre patógenos habitantes do solo e severidade de oídio da soja Effect of sewage sludge in soil-borne pathogens and powdery mildew severity in soybean

    Directory of Open Access Journals (Sweden)

    Fabio Fernando de Araújo

    2009-09-01

    Full Text Available O lodo de esgoto, atendendo as exigências ambientais, apresenta potencial para disposição em solos agrícolas. Sua incorporação altera as propriedades químicas, físicas e biológicas do solo, pois é rico em macro e micronutrientes e matéria orgânica. Estas alterações podem proporcionar benefícios como aumento da disponibilidade de nutrientes às culturas, indução de supressividade a fitopatógenos habitantes do solo e de resistência às doenças da parte aérea. Por outro lado, pode influenciar negativamente o equilíbrio biológico e químico no solo, devido à presença de contaminantes. O objetivo do trabalho foi avaliar os efeitos da incorporação de lodo de esgoto ao solo sobre a severidade de oídio (Erysiphe diffusa e na supressividade a Rhizoctonia solani e a Macrophomina phaseolina da soja (Glycine max. Para tanto, foram utilizados solos que receberam quatro aplicações (1999 a 2001 sucessivas de lodos de esgoto originários das Estações de Tratamento de Esgoto de Barueri e de Franca, SP, nas concentrações de 0, 1, 2, 4 e 8 vezes (0N a 8N a dose de N recomendada para a cultura do milho. Os estudos com oídio foram realizados em casa de vegetação com inoculação natural em dois cultivos sucessivos de soja. Também foi estudado o efeito de substrato produzido com 0%, 2,5%, 5% 10%, 15% e 20% de lodo de Franca sobre a emergência de plântulas e sobre a severidade de oídio da soja em três e dois ciclos, respectivamente. Nos estudos com R. solani e M. phaseolina, os solos foram artificialmente infestados com os patógenos e posteriormente cultivados com soja por dois ciclos, sendo avaliado o tombamento e a severidade das doenças. A aplicação de lodo de esgoto no solo aumentou a atividade eliciadora de fitoalexinas em soja e a severidade do oídio foi inversamente proporcional às concentrações do lodo, tanto no estudo com o solo de campo, como com o substrato obtido com o lodo de Franca. A emergência das pl

  2. Yellow-cedar in vitro clonal production and evaluation of propagules for reforestation. FRDA research memo No. 211

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Technical note describing a project that was part of an ongoing effort to develop micropropagation techniques on an operation scale and to investigate their possible use in producing genetically improved stock for planting. The project developed a commercially viable process that uses organogenic micropropagation to produce yellow-cedar stock for operational reforestation; evaluated the techniques for developing genetically improved clones; and established demonstration plots of mircopropagules.

  3. Quantification of propagules of the laurel wilt fungus and other mycangial fungi from the redbay ambrosia beetle, Xyleborus glabratus.

    Science.gov (United States)

    Harrington, T C; Fraedrich, S W

    2010-10-01

    The laurel wilt pathogen, Raffaelea lauricola, is a fungal symbiont of the redbay ambrosia beetle, Xyleborus glabratus, which is native to Asia and was believed to have brought R. lauricola with it to the southeastern United States. Individual X. glabratus beetles from six populations in South Carolina and Georgia were individually macerated in glass tissue grinders and serially diluted to quantify the CFU of fungal symbionts. Six species of Raffaelea were isolated, with up to four species from an individual adult beetle. The Raffaelea spp. were apparently within the protected, paired, mandibular mycangia because they were as numerous in heads as in whole beetles, and surface-sterilized heads or whole bodies yielded as many or more CFU as did nonsterilized heads or whole beetles. R. lauricola was isolated from 40 of the 41 beetles sampled, and it was isolated in the highest numbers, up to 30,000 CFU/beetle. Depending on the population sampled, R. subalba or R. ellipticospora was the next most frequently isolated species. R. arxii, R. fusca, and R. subfusca were only occasionally isolated. The laurel wilt pathogen apparently grows in a yeast phase within the mycangia in competition with other Raffaelea spp.

  4. Influence of Propagule Flotation Longevity and Light Availability on Establishment of Introduced Mangrove Species in Hawaiʻi

    Science.gov (United States)

    James A. Allen; Ken W. Krauss

    2006-01-01

    Although no mangrove species are native to the Hawaiian Archipelago, both (Rhizophora mangle) and (Bruguiera sexangula) were introduced and have become naturalized. (Rhizophora mangle) has spread to almost every major Hawaiian island, but (B. sexangula) has established only on O...

  5. Production and Field Planting of Vegetative Propagules for Restoration of Redhead Grass and Sago Pondweed in Chesapeake Bay

    Science.gov (United States)

    2009-08-01

    submerged aquatic vegetation (SAV) have been lost from shallow waters of Chesapeake Bay (Orth and Moore 1983) and other coastal ecosystems worldwide...a mixture of ambient estuarine water from the Choptank River (a tributary of Chesapeake Bay) and freshwater (tap) needed to maintain a salinity of 7...with a mixture of freshwater and ambient estuarine water (to maintain a salinity of 10) that was circulated through a closed- loop recirculation system

  6. Resistencia a sequía terminal en frijol negro tropical Comportamiento de variedades de maíz normal y con alta calidad de proteína para la región Golfo de México

    Directory of Open Access Journals (Sweden)

    Mark Frahm

    2003-01-01

    Full Text Available Con el objetivo de identificar cultivares de frijol negro tropical con resistencia a sequía y adaptación a la región Centroamericana, se diseñó un proyecto piloto colaborativo entre los programas de frijol de Zamorano, Honduras; Veracruz, México y la Universidad Estatal de Michigan (MSU; EE.UU, en el año 2002. Se desarrollaron dos poblaciones de líneas endog ámicas recombinantes (RILs derivadas de cruces entre la lí- nea resistente a sequía B98311 de MSU con TLP 19 y VAX 5, dos líneas mejoradas del CIAT con resistencia a enfermedades y adaptadas a las condiciones de América Central y México. Ambas poblaciones se evaluaron bajo riego y sequía terminal en Zamorano, Honduras y Veracruz, México. Los rendimientos se vieron reducidos por la sequía y por Macrophomina phaseolina, hongo causal de la pudrición carbonosa. El estrés por sequía, la presión de la enfermedad y los bajos rendimientos, contribuyeron a la obtención de altos coeficientes de variación, lo que hizo difícil la identificación y selecci ón de líneas superiores. La selección se basó en la posici ón de la media geométrica del rendimiento (MG calculada para cada línea con los datos de ambos tratamientos, riego y sequía. La línea L88-63 ocupó el primer lugar en la MG del rendimiento en ambas localidades. Evaluaciones posteriores conducidas en Honduras y Michigan, confirmaron el alto potencial de rendimiento y amplia adaptación de la línea L88- 63. El mejoramiento de la resistencia a la sequía en ambientes del trópico bajo, requiere la incorporación adicional de resistencia a M. phaseolina en las nuevas líneas consideradas para liberarse como nuevas variedades en esta región.

  7. Effect of composts on microbial dynamics and activity, dry root rot severity and seed yield of cowpea in the Indian arid region

    Directory of Open Access Journals (Sweden)

    Meenu BAREJA

    2011-01-01

    Full Text Available Nutrient-deficient sandy soil, having poor moisture retention, favors  Macrophomina phaseolina, a soil-borne plant pathogen, occurring in severe form on many important crops grown in the Indian arid region. In a 2-year field experiment, five composts (4 ton/ha prepared from residues of Calotropis procera, Prosopis juliflora, Azadirachta indica, Acacia nilotica, and on-farm weeds were tested on cowpea (Vigna unguiculata to determine their effectiveness in limiting the  severity of charcoal rot caused by M. phaseolina in relation to the microbial population dynamics, microbial activity and the seed yield of cowpea.  In general, compost-amended plots retained 8.9% higher moisture than unamended plots. The microbial population increased in amended plots during the crop season. Populations of total fungi and actinomycetes were heighest in Calotropis compost-amended soil, while total bacteria were maximum in weed- compost amended soil. Microbial activity in amended plots was  26.3% higher than in unamended plots. Among trace elements,  uptake of Zn, Mn, Fe and Cu was  heighest  in plants grown in weed-compost amended soil followed by A. nilotica compost-amended soil. Soil amendment with the composts significantly reduced  plant mortality due to charcoal rot. The lowest mortality was recorded in plants amended with A. nilotica compost (5.5% followed by P. juliflora compost (5.8, while the  highest plant mortality (11.5% from charcoal rot occurred in the unamended control on the basis of the pooled average of two years. There was a significant inverse correlation between microbial activity and charcoal rot incidence in cowpea at 20 days after planting. Composts also had a beneficial effect on yield, with a 28.3% increase in seed yield in P. juliflora compost-amended plots. These results suggest that in resource-deficient farming , certain on-farm wastes can be effectively utilized for managing soil-borne pathogens, as well as  for

  8. Sobrevivência de fungos fitopatogênicos habitantes do solo, em microcosmo, simulando solarização com prévia incorporação de materiais orgânicos Survival of soilborne plant pathogenic fungi in soil solarization simulation (microcosm associated with the incorporation of organic materials

    Directory of Open Access Journals (Sweden)

    Márcia Michelle de Queiroz Ambrósio

    2009-02-01

    Full Text Available Os fungos fitopatogênicos habitantes do solo podem sobreviver por vários anos nesse ambiente por meio de estruturas de resistência, causando perdas em muitas culturas, por vezes, inviabilizando o pleno aproveitamento de vastas áreas agrícolas. O uso de materiais orgânicos no solo consorciado com a técnica de solarização propicia a retenção de compostos voláteis fungitóxicos emanados da rápida degradação dos materiais e que são letais a vários fitopatógenos. O objetivo deste experimento foi à prospecção de novos materiais orgânicos que produzissem voláteis fungitóxicos capazes de controlar fungos fitopatogênicos habitantes do solo, em condições de associação com a simulação da técnica de solarização (microcosmo. Portanto, o presente trabalho consistiu de seis tratamentos (Solarizado; Solarizado+Brócolos; Solarizado+Eucalipto; Solarizado+Mamona; Solarizado+Mandioca e Laboratório e cinco períodos (0, 7, 14, 21 e 28 dias para avaliar a sobrevivência de quatro fungos de solo (Fusarium oxysporum f. sp. lycopersici Raça 2; Macrophomina phaseolina; Rhizoctonia solani AG-4 HGI e Sclerotium rolfsii. Em cada uma das duas câmaras de vidro (microcosmo por dia avaliado continha uma bolsa de náilon contendo as estruturas de resistência de cada fitopatógeno. Estruturas dos fitopatógenos foram mantidas também em condições de laboratório como referencial de controle. Todos os materiais quando associados à simulação da solarização propiciaram o controle de todos os fitopatógenos estudados, entretanto, foi observado variação no controle dos fungos. O tratamento que apenas simulou a solarização não controlou nenhum fitopatógeno.Soilborne phytopathogenic fungi can survive for several years in Laboratory and five periods (0, 7, 14, 21 and 28 days to evaluate soil through resistance structures and it causes losses in several crops the survival of four soil fungi (Fusarium oxysporum f. sp. lycopersici making

  9. Evaluation of biochemical component and antimicrobial activity of some seaweeeds occurring at Karachi coast

    International Nuclear Information System (INIS)

    Ambreen, A.; Hira, K.; Ruqqia, A.; Sultana, V.

    2012-01-01

    Nutritionally valuable seaweeds are being used as fresh or dried vegetables or as ingredients in wide variety of prepared foods. Interest in seaweeds has increased markedly through out the world due to their value in nutrition and in medicine. In this study 16 seaweed species collected from Karachi coast were examined for the estimation of ascorbic acid (vitamin C), calcium and 9 for protein, carbohydrate and lipid contents. Lipid content was found less as compared to carbohydrate and protein in most of the brown and red seaweeds. All the seaweeds showed the presence of calcium at varying concentrations, while ascorbic acid was found in fourteen seaweeds in considerable amount. Intake of edible seaweeds having ascorbic acid and calcium may protect the human from the diseases related to deficiency of calcium and vitamin C. Microbes and microbial infection remains a threat to human life. In this study, ethanol extract of 5 seaweeds were screened for antibacterial activity, while 9 tested against root rotting fungi. Most of the brown species had shown potent antimicrobial activity followed by red algal species. The highest antibacterial activity was found in ethanol extract of brown seaweed species Dictyota dichotoma var intricata and D. indica against Salmonella typhimurium followed by D. indica and Halimeda tuna against Bacillus subtilis with a zone of inhibition of 15, 15, 14, and 14 mm respectively. Dictyota dichotoma var. intricata, D.indica, Sargassum lanceolatum and red Melanothamnus afaqhusainii produced a zone of inhibition of 11, 10, 9, 11mm respectively against gram negative bacteria Salmonella typhimurium even at lowest concentration of 2mg/disc. The ethanol extract of most of the species was found less active against tested fungi (Rhizoctonia solani, Macrophomina phaseolina, Fusarium solani and F. oxysporum). Only two brown seaweeds Sargassum ilicifolium and Cystoseira indica had shown antifungal activity to some extent. (author)

  10. Rhizoctonia root rot (Rhizoctoni solani K ü h n of sugar beet in province Vojvodina

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    Stojšin Vera B.

    2006-01-01

    Full Text Available Sugar beet root rot appears regularly each year, but its intensity depends on agro ecological conditions. The predominant causers of root rot in Vojvodina are fungi from Fusarium genus and species Macrophomina phaseolina. Over the last couple of years, more intense occurrence of Rhizoctonia root rot has been observed. Rhizoctonia solani, the causal agent of root rot is present in sugar beet fields. During 2000-2005, on the territory of Vojvodina, the frequency of Rhizoctonia solani in phytopathological isolations from rotted sugar beet roots was between 0,0-18,2%. The intensity of the disease depends on localities, agro ecological conditions and genotypes. Symptoms of Rhizoctonia root rot were registered at some localities in all regions of Vojvodina: Srem, Banat and Bačka. The disease appearance is above all local. It occurs in small patches, on heavy, non-structured soil and on depressed wet parts of plots. Individual diseased plants can be found during July. Brown rot appears on sugar beet roots, with dried tissue on surface, which is present on the tail as well as on the middle part and the head of root. Tissues with described symptoms are deeper regarding the healthy part of root. On vertical root section, the necrotic changes are clearly visible comparing to tissue section without symptoms. The heavily infected tissue forms fissures on roots in most cases. Besides the above-mentioned symptoms on roots, the plant wilting and leaf handle necrosis as well as leaf dying are also observed. When rot spreads to the whole root head, plants quickly die.

  11. Seedborne Pathogenic Fungi in Common Bean (Phaseolus vulgaris cv. INTA Rojo) in Nicaragua.

    Science.gov (United States)

    Marcenaro, Delfia; Valkonen, Jari P T

    2016-01-01

    Common bean (Phaseolus vulgaris L.) is an important legume with high nutritional value. In Nicaragua, certified healthy seeds of local bean varieties are not available, and seedborne fungi have gained little attention. Here, were surveyed seedborne pathogenic fungi in an important local bean cultivar, 'INTA Rojo'. Beans grown in the four main production areas in Nicaragua (Boaco, Carazo, Estelí, Matagalpa) for future use as seed stock were sampled from four seed storehouses and six seed lots. A total of 133 fungal strains were isolated from surface-sterilized beans and inoculated to healthy lima beans (Phaseolus lunatus) under controlled conditions. Eighty-seven isolates caused symptoms of varying severity in the seedlings, including discoloration, necrotic lesions, cankers, rot, and lethal necrosis. Pathogenic isolates were divided into eight phenotypically distinguishable groups based on morphology and growth characteristics on artificial growth medium, and further identified by analysis of the internal transcribed spacer sequences (ITS1 and ITS2) of the ribosomal RNA genes. The pathogenic isolates belonged to eight genera. Fusarium spp. (F. chlamydosporum, F. equiseti, F. incarnatum), Lasiodiplodia theobromae, Macrophomina phaseolina, and Penicillium citrinum were the most damaging and common fungi found in the seed lots. Furthermore, Corynespora cassiicola, Colletotrichum capsisi, Colletotrichum gloeosporioides, Aspergillus flavus, and Diaporthe sp. (Phomopsis) were seedborne in cultivar 'INTA Rojo' and found to be pathogenic to bean seedlings. This study reveals, for the first time, many seedborne pathogenic fungi in beans in Nicaragua; furthermore, prior to this study, little information was available concerning F. equiseti, F. incarnatum, L. theobromae, C. cassiicola, and Diaporthe spp. as seedborne pathogens of common bean. Our results lay the basis for developing diagnostic tools for seed health inspection and for further study of the epidemiology

  12. Occurrence and identification of the etiologic agents of plant diseases in cactus (Opuntia ficus-indica Mill. in the semi-arid region of Paraiba

    Directory of Open Access Journals (Sweden)

    Anne Evelyne Franco de Souza

    2010-01-01

    Full Text Available Cactus forage (Opuntia ficus-indica Mill., intensely cultivated in dry regions of northeast Brazil, although well adapted to the harsh semi-arid climate is affected by major problems such as pests and diseases, responsible for significant losses in production. This study aimed to investigate the occurrence and diversity of the etiologic agents of diseases of cactus cultivated in 38 municipalities in the semi-arid region of Paraiba. The analyses were conducted and processed at the Laboratory of Phytopathology of the Centro de Ciências Agrárias da Universidade Federal da Paraíba, in Areia - PB. Starting from sick cladodes isolations, multiplications and identifications of the found microorganisms were made. The identification of the microorganisms was achieved through observations of the macro and micromorphological characteristics of the cultures and tests of Gram and pathogenicity. Great incidence and diversity of microorganisms was verified in the cacti researched, but the highest occurrence was mainly that of fungus. The fungi of widest occurrence were: Scytallidium lignicola, Alternate tenuis, Macrophomina phaseolina, Cladosporium cladosporides, Lasiodiplodia theobromae, Fusarium oxysporum f. sp. opuntiarum, Curvularia lunata, Aspergillus niger, Nigrospora sphaerica, Colletotrichum gloeosporioides, Exserohilum turcicum, Pestalotia pitospora, Rhizopus stolonifer, Rhizoctonia solani and Sphaceloma protearum. A bacterium was also detected that was suspected to belong to the Erwinia sp. strain. Satisfaction of the Postulates of Koch proved the infectious nature of the detected microorganisms. High occurrence of the fungus S. lignicola, an agent of scale rot disease in 100% of the places researched, was observed. This fact is of great concern, since the progression of the disease can cause significant losses in production.

  13. Banana peel culture as an indigenous medium for easy identification of late-sporulation human fungal pathogens.

    Science.gov (United States)

    Kindo, A J; Tupaki-Sreepurna, A; Yuvaraj, M

    2016-01-01

    Fungi are increasing in incidence as human pathogens and newer and rarer species are continuously being encountered. Identifying these species from growth on regular culture media may be challenging due to the absence of typical features. An indigenous and cheap medium, similar to the natural substrate of these fungi, was standardised in our laboratory as an aid to species identification in a conventional laboratory setting. Ripe banana peel pieces, sterilised in an autoclave at 121°C temperature and 15 lbs pressure for 15 min promoted good growth of hyphae and pycnidia or acervuli in coelomycetes, flabelliform and medusoid fruiting bodies of basidiomycetes and fruit bodies such as cleistothecium in ascomycetes. The growth from the primary isolation medium was taken and inoculated onto the pieces of double-autoclaved ripe banana peel pieces in a sterile glass Petri dish with some moisture (sprinkles of sterile distilled water). A few sterile coverslips were placed randomly inside the Petri dish for the growing fungus to stick on to it. The plates were kept at room temperature and left undisturbed for 15-20 days. At a time, one coverslip was taken out and placed on a slide with lactophenol cotton blue and focused under the microscope to look for fruit bodies. Lasiodiplodia theobromae, Macrophomina phaseolina, Nigrospora sphaerica, Chaetomium murorum, Nattrassia mangiferae and Schizophyllum commune were identified by characteristic features from growth on banana peel culture. Banana peel culture is a cheap and effective medium resembling the natural substrate of fungi and is useful for promoting characteristic reproductive structures that aid identification.

  14. Biocontrol of certain soilborne diseases and promotion of growth of capsicum annuum using biofungicides

    International Nuclear Information System (INIS)

    Madbouly, A.; Abdelbacki, A.M.M.

    2017-01-01

    Colored pepper (Capsicum annuum L.) has great economic importance as a food vegetable crop in Egypt and all over the world. This crop is prone to infection with soilborne fungal pathogens such as Rhizoctonia solani, Fusarium solani and Macrophomina phaseolina. These mycopathogens were isolated from diseased pepper seedlings, identified; their virulence was confirmed in the greenhouse. Eight bacterial isolates mainly; (Bacillus subtilis and Pseudomonas fluorescens), and many fungal isolates mainly, (Trichoderma harzianum and T. viride), were isolated from the rhizosphere soil of pepper. They caused appreciable In vitro inhibition of the radial growth of the 3 pathogens in dual culture technique, in percentages ranging from (71-79%) and (80-87%), respectively. On infestation of pepper soil with these bioagents and the 3 pathogens separately in the greenhouse, they caused In vivo reduction of disease symptoms of pepper compared with the pathogens infested and non-infested control soils. In addition, they caused significant improvement of pepper growth compared with the control soil, however, promotion exerted by B. subtilis and T. harzianum was more than that of P. fluorescens and T. viride. These promoting activities could be attributed to the production of metabolites such as growth hormones; solubilization of phosphates and improvement of nutrient uptake. This is the first record of promoting the growth of pepper in greenhouse by B. subtilis and T. harzianum in Egypt. Thus these bioagents could be formulated then applied in the future in pepper fields of this country as safe, effective, ecofriendly biofungicides to control soilborne pathogens and also could be used as biofertilizers to promote the growth and productivity of this crop. (author)

  15. Microflora en semillas de frijol

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    Jos\\u00E9 B. Membre\\u00F1o

    2001-01-01

    Full Text Available Microflora en semillas de frijol (Phaseolus vulgaris L.. Se estudió la microflora bacteriana presente en semillas de frijol y su relación con Xanthomonas campestris pv. phaseoli (Xcp, en 118 genotipos procedentes de VIDAC-98, INTA- Nicaragua, TARS-USDA e Isabela-P.R. Se utilizaron cinco métodos de aislamiento: semilla desinfectada con hipoclorito de sodio, semilla en caldo nutritivo refrigerada por una hora, dispersión de 0,1 ml de suspensión de semillas en medio sólido, siembra líquida de 1 ml de suspensión y semilla en caldo nutritivo, agitado y refrigerado por 24 horas. Se aislaron 104 colonias amarillas de 41 genotipos. Treinta y seis colonias fueron KOH positivo (Gram negativo, 68 negativo (Gram positivo y 34 hidrolizaron almidón. Las colonias de pigmentación amarilla resultaron no patogénicas bajo condiciones de invernadero. Estas se identificaron con el sistema BIOLOG como: Pantoea agglomerans (25, Xanthomonas campestris (2, Enterobacter agglomerans (2, Sphingomonas paucimobilis (2, Pseudomonas fluorescens y Flavimonas oryzihabitans. En adición, los genotipos portaron colonias con pigmentación distinta a la amarilla. En las pruebas de antagonismo se identificaron colonias con actividad de deoxyribonucleasa y de antibiosis a Xcp. De éstas, 15 colonias inhibieron a Xcp significativamente. Se identificaron los hongos Rhizoctonia solani, Penicillium spp., Fusarium spp., Aspergillus flavus, Rhizopus nigricans y Macrophomina phaseolina en un 52,9 % del total de genotipos evaluados

  16. Seed-storage Mycoflora of Peanut Cultivars Grown in Nigerian Savanna

    Directory of Open Access Journals (Sweden)

    Nwankiti, AO.

    2003-01-01

    Full Text Available Storage of peanut is increasingly becoming important both among growers and users of the crop in Nigerian savanna. The aim is to sell the produce and maximize benefits accruing from the crops during scarcity. Very often, these envisaged advantages fail due to unfavourable market forces, thus compelling them to sell at a loss or store them across seasons for periods ranging from one to two years. However, information on fungi associated with storage of such peanuts in Nigerian savanna and its attendant problems are yet to be investigated. Thus, the seed mycoflora and viability seven common peanut cultivars stored under conditions similar to traditional settings were investigated using different isolating techniques. The peanut cultivars were RMP 12, RMP 91, RRB, 48-115B, M554-76, 55-437 Ex-Dakar and a local cultivar. None of these cultivars possessed resistance to in vitro colonization by fungi. Aspergillus niger, Aspergillus flavus and Rhizopus stolonifer were consistently isolated from all the cultivars from almost all isolating techniques. Other fungi were Fusarium chlamydosporium, F. roseum, F. oxysporium, Penicillium spp., Curvularia spp., Botryodiplodia theobromae, Macrophomina phaseolina and Sclerotium rolfsii. Relative percentages, however, varied with individual fungi and peanut cultivars. The test with seven different types of growth media gave the highest fungi recovery rate than the blotter paper technique. Seed viability was lower with peanut seeds stored for two years. Also, the relative percentage occurrence of individual fungi was significantly higher with seeds stored for two years. While we recommend the use of growth media for recovery and study of seed mycoflora, peanut seeds should not be stored for more than one year.

  17. ENFERMEDADES Y COMPONENTES DE RENDIMIENTO EN LÍNEAS DE FRÉJOL BAJO TRES DENSIDADES DE SIEMBRA

    Directory of Open Access Journals (Sweden)

    Felipe Rafael Garc\\u00E9s-Fiallos

    2014-01-01

    Full Text Available El objetivo fue evaluar las enfermedades, el rendimiento y sus componen - tes en líneas de fréjol bajo tres distanciamientos de siembra. El trabajo se realizó durante la época seca del año 2011, en la Universidad Técnica Estatal de Quevedo (UTEQ, Quevedo, Ecuador. Se determinó la incidencia y severidad de la roya ( Uromyces appendiculatus y mustia hilachosa ( Rizoctonia solani en los estadíos R7 (formación en legumbres y R8 (llenado de legumbres, y después de la cosecha la incidencia de las pudriciones radiculares ( Macrophomina phaseolina y R. solani . Los componentes de rendimiento (número de nudos, legumbres, granos, granos por legumbre, legumbres estériles y granos por planta y peso de granos. Se empleó un Diseño de Bloques Completos al Azar (DBCA con doce tratamientos y tres repeticiones, con arreglo factorial de 4 (líneas promisorias x 3 (planta/m. Para la comparación entre las medias de los tratamientos se empleó la prueba de Tukey al 5% de probabilidad del error. Las líneas promisorias de fréjol EVG 06-103 y SER-03 presentaron menor intensidad de enfermedades. Un aumento en la densidad poblacional causó un acrecentamiento en la intensidad de la roya. Las líneas SER-08 y SER-03 obtuvieron la mayor productividad según la mayoría de componentes de rendimiento y peso de granos. Finalmente, el incremento de la densidad de plantas promovió reducción significativa en el número de legumbres, granos y granos por legumbre por planta, contrario al aumento observado en el peso de granos

  18. Mass development of monospecific submerged macrophyte vegetation after the restoration of shallow lakes: roles of light, sediment nutrient levels, and propagule density

    NARCIS (Netherlands)

    Verhofstad, M.J.J.M.; Alirangues, Marta Maria; Reichman, Erik; van Donk, E.; Lamers, L.P.M.; Bakker, E.S.

    2017-01-01

    Abstract After restoration, eutrophicated shallow freshwaters may show mass development of only one or two submerged macrophyte species, lowering biodiversity and hampering recreation. It is unclear which environmental factors govern this high percentage of the volume inhabited (PVI11 PVI: The

  19. Mass development of monospecific submerged macrophyte vegetation after the restoration of shallow lakes: Roles of light, sediment nutrient levels, and propagule density

    NARCIS (Netherlands)

    Verhofstad, M.J.J.M.; Alirangues Núñez, M. M.; Reichman, E. P.; van Donk, E.; Lamers, L. P.M.; Bakker, E. S.

    2017-01-01

    After restoration, eutrophicated shallow freshwaters may show mass development of only one or two submerged macrophyte species, lowering biodiversity and hampering recreation. It is unclear which environmental factors govern this high percentage of the volume inhabited (PVI2) by submerged

  20. Use of the vital stain FUN-1 indicates viability of Phytophthora capsici propagules and can be used to predict maximum zoospore production.

    Science.gov (United States)

    Lewis Ivey, Melanie L; Miller, Sally A

    2014-01-01

    The fluorescent vital dye FUN®-1 (2-chloro-4-[2,3-dihydro-3-methyl-{benzo-1,3-thiazol-2-yl}-methylidene]-1-phenylquinolinium iodide) was evaluated as a tool to assess Phytophthora capsici sporangia and zoospore metabolic activity and viability. Under aerobic conditions, mycelia, sporangia and zoospores cultured on agar medium and stained with FUN-1 exhibited red fluorescent cylindrical intravacuolar structures (CIVS) that were clearly visible at 100× magnification. Encysted zoospores did not exhibit CIVS after exposure to FUN-1 dye. Over 7 d there was a significant reduction in the percent of sporangia containing CIVS, which corresponded with a significant increase in zoospore formation and release. The decline in the percentage of metabolically active sporangia and increase in the number of zoospores fit both a linear and log regression model. The FUN-1 dye was suitable for distinguishing between live and dead sporangia and effective in monitoring the change in metabolic activity of sporangia over time. It will be useful in determining parameters, including P. capsici culture age, that maximize production of zoospores in vitro.

  1. Evaluation of genetic variability in micropropagated propagules of ornamental pineapple [Ananas comosus var. bracteatus (Lindley) Coppens and Leal] using RAPD markers.

    Science.gov (United States)

    Santos, M D M; Buso, G C S; Torres, A C

    2008-10-21

    The objective of the present study was to evaluate the genetic variability in micropropagated plantlets of ornamental pineapple, after the fourth period of subculture. The basal culture medium consisted of MS salts, vitamins, 3% sucrose, liquid formulation, supplemented with 6-benzylaminopurine (BAP) at concentrations of 0.125, 0.25, 0.5, 1.0, and 2.0 mg/L. The addition of BAP influenced the occurrence of genetic variation revealed using random amplified polymorphic DNA (RAPD) markers. Of a total of 520 primers tested, 44 were selected and amplified; 402 monomorphic bands (97.2%) and 18 polymorphic bands (2.8%) resulted among regenerated plantlets. The polymorphic fragments were produced by 12 primers (OPA-01, OPA-20, OPB-01, OPB-19, OPC-19, OPF-13, OPL-17, OPM-13, OPP-16, OPT-07, OPV-19, and OPX-03). Among the primers that identified polymorphism, OPA-01, OPA-20, OPB-19, OPC-19, OPL-17, OPP-16, and OPX-3 each showed, one polymorphic band and OPF-13 amplified a maximum of three bands. In this study, the RAPD technique was effective in showing the occurrence of somaclonal variations that occur during the micropropagation process of ornamental pineapple cultivation in BAP-supplemented medium, and it is possible to detect the presence of genetic variation in early stages of plant development.

  2. La marchitez tardía del maíz (Zea mays L. causada por Cephalosporium maydis en la Península Ibérica, y otros hongos asociados

    Directory of Open Access Journals (Sweden)

    Carmen Maria Ortiz-Bustos

    2015-06-01

    Full Text Available Las especies de hongos de suelo asociadas a Cephalosporium maydis como agente causal de la marchitez tardía del maíz en la Península Ibérica se identificaron muestreando 19 campos con síntomas de marchitez en las principales zonas de cultivo entre 2011 y 2012. En el 47% de los campos no se identificó C. maydis, pero sí Fusarium graminearum, F. verticillioides, F. equiseti, F. proliferatum, Macrophomina phaseolina, Rhizoctonia solani y Trichoderma harzianum infectando las plantas de maíz. En los campos restantes, junto a C. maydis se identificaron otros hongos de suelo en porcentajes apreciables: F. verticillioides (19%, F. proliferatum (19%, F.equiseti (9%, F. oxysporum (9% y Pythium oligandrum (9%. El crecimiento vascular de C. maydis y de otras especies fúngicas en plantas de maíz se confirmó analizando plantas con marchitez procedentes de tres campos diferentes. Tanto C. maydis como F. graminearum, F. equiseti, F. proliferatum y T. harzianum se aislaron de la inserción entre la raíz y tallo y a 10 cm de altura en el tallo de las plantas. El efecto de la infección por C. maydis sobre la producción de las plantas de maíz se cuantificó en macetas y condiciones seminaturales en el 2011. En plantas inoculadas se obtuvo una reducción del peso de las mazorcas del 54%, además de pesos de raíz y de parte aérea (tallo y hojas significativamente menores en comparación con el control no inoculado, lo que sugiere el gran impacto económico que puede tener la marchitez tardía en condiciones naturales. Asimismo este trabajo pone de manifiesto el grado de complejidad de la etiología de la marchitez tardía, que debería ser estudiado mediante la confirmación de la patogenicidad de los hongos de suelo identificados en maíz, con el fin de determinar el papel que puede jugar cada una de estas especies en el desarrollo de la enfermedad y/o severidad de los síntomas.

  3. Synthesis of some potent immunomodulatory and anti-inflammatory metabolites by fungal transformation of anabolic steroid oxymetholone

    Directory of Open Access Journals (Sweden)

    Khan Naik Tameen

    2012-12-01

    Full Text Available Abstract Background Biotransformation of organic compounds by using microbial whole cells provides an efficient approach to obtain novel analogues which are often difficult to synthesize chemically. In this manuscript, we report for the first time the microbial transformation of a synthetic anabolic steroidal drug, oxymetholone, by fungal cell cultures. Results Incubation of oxymetholone (1 with Macrophomina phaseolina, Aspergillus niger, Rhizopus stolonifer, and Fusarium lini produced 17β-hydroxy-2-(hydroxy-methyl-17α-methyl-5α-androstan-1-en-3-one (2, 2α,17α-di(hydroxyl-methyl-5α-androstan-3β,17β-diol (3, 17α-methyl-5α-androstan-2α,3β,17β-triol (4, 17β-hydroxy-2-(hydroxymethyl-17α-methyl-androst-1,4-dien-3-one (5, 17β-hydroxy-2α-(hydroxy-methyl-17α-methyl-5α-androstan-3-one (6, and 2α-(hydroxymethyl-17α-methyl-5α-androstan-3β-17β-diol (7. Their structures were deduced by spectral analyses, as well as single-crystal X-ray diffraction studies. Compounds 2–5 were identified as the new metabolites of 1. The immunomodulatory, and anti-inflammatory activities and cytotoxicity of compounds 1–7 were evaluated by observing their effects on T-cell proliferation, reactive oxygen species (ROS production, and normal cell growth in MTT assays, respectively. These compounds showed immunosuppressant effect in the T-cell proliferation assay with IC50 values between 31.2 to 2.7 μg/mL, while the IC50 values for ROS inhibition, representing anti-inflammatory effect, were in the range of 25.6 to 2.0 μg/mL. All the compounds were found to be non-toxic in a cell-based cytotoxicity assay. Conclusion Microbial transformation of oxymetholone (1 provides an efficient method for structural transformation of 1. The transformed products were obtained as a result of de novo stereoselective reduction of the enone system, isomerization of double bond, insertion of double bond and hydroxylation. The transformed products, which showed significant

  4. Deterioration and spoilage of peanuts and desiccated coconuts from two sub-Saharan tropical East African countries due to the associated mycobiota and their degradative enzymes.

    Science.gov (United States)

    Ismail, M A

    2001-01-01

    A broad variety of fungi (84 species belonging to 36 genera) were identified with more taxa infesting peanut seed samples from two tropical countries (29 genera and 61 species) compared to those found in desiccated coconuts (20 genera and 55 species) on both DRBC and DG18 media. This may be due to the higher moisture levels in peanuts (5.07-7.97%) compared with coconuts (1.5-4.17%). More taxa and propagules were recovered on DG18 in both cases. The dominant fungi from both substrates on both isolation media were Aspergillus and Penicillium, with other fungi from only one substrate/medium. The aflatoxigenic species (A. flavus) dominated Kenyan samples more so than Ugandan samples on both substrates. However only 71.5% and 87.5% of the peanut kernels, on DRBC and DG18, respectively, were found to be infested with fungi. The aflatoxigenic species (A. flavus/parasiticus) were found in 75% of the samples, however only 15.75% and 13% of the kernels analyzed were infested. The most frequently isolated species from peanuts were A. niger followed by A. flavus and M. phaseolina. E. repens, E. amstelodami, E. rubrum and E. chevalieri dominated peanut seeds on DG18, and R. stolonifer, A. parasiticus, F. solani, L. theobromae and P. chrysogenum on DRBC. The mean count of fungal propagules in coconut samples were approximately 0.7 x 10(3) and 0.8 x 10(3) on DRBC and DG18, respectively, with a high proportion of those propagules recorded for the aflatoxigenic species (about 0. 17 x 10(3) and 0.25 x 10(3) colonies/g). The mycobiota of desiccated coconut was dominated by A. niger, A. flavus and P. chrysogenum. Also A. ochraceus, P. waksmanii, Paecilomyces variotii, P. islandicum and R. mucilaginosa were more frequent on DRBC, while, species of Cladosporium. Chrysosporium and Eurotium were more frequent on DG18. Enzyme indices (or the activities) for each specific strain, when determined after 5 and 8 days of incubation, proved to be similar. A recommendation is given. The

  5. Complete life cycle of the lichen fungus Calopadia puiggarii (Pilocarpaceae, Ascomycetes) documented in situ: propagule dispersal, establishment of symbiosis, thallus development, and formation of sexual and asexual reproductive structures.

    Science.gov (United States)

    Sanders, William B

    2014-11-01

    The life histories of lichen fungi are not well known and cannot be readily studied in laboratory culture. This work documents in situ the complete life cycle of the widespread crustose lichen Calopadia puiggarii, which reproduces sexually and asexually on the surfaces of leaves. Plastic cover slips held in a mesh frame were placed over leaves in the field and successively removed for microphotography of colonizing lichens. Macroconidia produced within campylidia encircled photobiont cells and codispersed with them, a feature not reported previously for C. puiggarii. Dispersed macroconidia readily germinated and lichenized the photobionts. Algal cells were often dislodged from the encircling macroconidia, providing a likely source for the free-living populations observed. Aposymbiotically dispersed ascospores germinated and lichenized nearby algal cells soon after dispersal. Thallus areolae merged readily in early development, although adjacent mature thalli were often separated by growth inhibition zones. Pycnidia are reported for the first time in Calopadia; their pyriform microconidia probably function as male gametes (spermatia). Pycnidia, apothecia, and campylidia began development similarly as darkly pigmented primordia on the fungal prothallus. Abundant dispersal of ascospores, conidia, and photobionts allows C. puiggarii to quickly colonize leaves with the dual advantages of sexual and asexual reproduction, and with the added convenience of having its algal partner on hand. Fusions and prothallic capture of additional algae provide many opportunities for multiple mycobiont and photobiont genotypes to be combined in a single thallus, but the outcomes of such events remain to be explored. © 2014 Botanical Society of America, Inc.

  6. Dispersion and establishment of the species of mangrove of the Rancheria River in the period of maximum fructification

    International Nuclear Information System (INIS)

    Lema Velez, Luisa Fernanda; Polania, Jaime; Urrego Giraldo, Ligia Estela

    2003-01-01

    Dispersion and establishment patterns of Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa, at the Rancheria River were studied using marked propagules. These mangroves are small, and surrounded by subtropical dry forest, subtropical thorn forest and the city of Riohacha. Significant relationships were found between the number of propagules retained and species, time, distance to release site, and retention structure. Avicennia germinans and L. racemosa propagules left the ecosystem within two weeks while a portion of R. mangle propagules remained during the two months study and were able to settle. Goat predation affected mainly the propagules, especially of A. germinans and L. racemosa. Predation did not follow the current dominance-predation model. A pre-dispersion consumption of 30% of A. germinans propagules by Pyralidae larvae was also documented. Batis maritima plants were the most effective structures that retain propagules of the three species and R. mangle propagules remained in greater quantities and for longer periods in the ecosystem

  7. Determination of mycoflora of pea (Pisum sativum) seeds and the ...

    African Journals Online (AJOL)

    Jane

    2011-07-06

    Jul 6, 2011 ... The most common isolated fungi were Fusarium spp., Alternaria spp., Macrophomina ... known to affect the plant growth directly by producing ..... Evaluation of bacterial epiphytes isolated from avocado leaf and fruit surfaces ...

  8. Extraction and Identification of Secondary Metabolites Produced by Trichoderma atroviridae (6022 and Evaluating of their Antifungal Effects

    Directory of Open Access Journals (Sweden)

    M. Shahiri Tabarestani

    2017-08-01

    capacity of Trichoderma species in crop protection and promoting vegetative growth, they are marketed as biopesticides, biofungicides and biofertilizers. The identification of molecules with such biological activities can support the development of new biopesticides and biofertilizers based on Trichoderma metabolites. The aim of this study was to investigate antifungal effects and chemical composition of secondary metabolites produced by Trichoderma atroviridae(6022 against Macrophomina phaseolina and Sclerotinia sclerotiorum. Materials and Methods: Antifungal effects of isolate 6022 against M. phaseolina and S. sclerotiorum were evaluated under invitro condition by dual culture technique, volatile (Dennis & Webster 1971 and non-volatile (Vinal 2006 metabolites. Volatile metabolites tests were done in 4 cases: Co-culture, 24, 48 and 72 hour cultures. For considering non-volatile metabolites of this isolate, different concentrations of culture filtrate and mycelial mass have been prepared in (autoclaved potato dextrose agar (PDA, individually. Secondary metabolites were extracted via 4 processes by using of organic solvents (Siddiquee 2012, Headspace technique (Stoppacher 2010 and soxhlet water bath distillation methods for mycelial mass (Dubey 2011 and identified by using the GC-MS device with nonpolar column (DB-5. Results and Discussion: In dual culture test, isolate 6022 inhibited the mycelial growth of the pathogen, then over ran and sporulated on the mycelia. The related results for the volatile test in 24, 48, 72h and Co-cultures, indicated that the antagonist inhibited the mycelial growth of the pathogen and production of sclerotia in culture media (PDA. Results of the non-volatile test (in different concentrations showed significant inhibitory effects on mycelial growth and production of sclerotia. After extraction and GC separation, the constituents of mixtures can be detected via mass spectrometry (MS by comparison of mass spectra with library spectra searching

  9. Interaction between water and wind as a driver of passive dispersal in mangroves.

    Directory of Open Access Journals (Sweden)

    Tom Van der Stocken

    Full Text Available Although knowledge on dispersal patterns is essential for predicting long-term population dynamics, critical information on the modalities of passive dispersal and potential interactions between vectors is often missing. Here, we use mangrove propagules with a wide variety of morphologies to investigate the interaction between water and wind as a driver of passive dispersal. We imposed 16 combinations of wind and hydrodynamic conditions in a flume tank, using propagules of six important mangrove species (and genera, resulting in a set of dispersal morphologies that covers most variation present in mangrove propagules worldwide. Additionally, we discussed the broader implications of the outcome of this flume study on the potential of long distance dispersal for mangrove propagules in nature, applying a conceptual model to a natural mangrove system in Gazi Bay (Kenya. Overall, the effect of wind on dispersal depended on propagule density (g l(-1. The low-density Heritiera littoralis propagules were most affected by wind, while the high-density vertically floating propagules of Ceriops tagal and Bruguiera gymnorrhiza were least affected. Avicennia marina, and horizontally floating Rhizophora mucronata and C. tagal propagules behaved similarly. Morphological propagule traits, such as the dorsal sail of H. littoralis, explained another part of the interspecific differences. Within species, differences in dispersal velocities can be explained by differences in density and for H. littoralis also by variations in the shape of the dorsal sail. Our conceptual model illustrates that different propagule types have a different likelihood of reaching the open ocean depending on prevailing water and wind currents. Results suggest that in open water, propagule traits (density, morphology, and floating orientation appear to determine the effect of water and wind currents on dispersal dynamics. This has important implications for inter- and intraspecific

  10. Inconsistencies among secondary sources of Chukar Partridge (Alectoris chukar) introductions to the United States

    OpenAIRE

    Moulton, Michael P.; Cropper, Wendell P.; Broz, Andrew J.

    2015-01-01

    The propagule pressure hypothesis asserts that the number of individuals released is the key determinant of whether an introduction will succeed or not. It remains to be shown whether propagule pressure is more important than either species-level or site-level factors in determining the fate of an introduction. Studies claiming to show that propagule pressure is the primary determinant of introduction success must assume that the historical record as reported by secondary sources is complete ...

  11. Role of Bradyrhizobium japonicum and Trichoderma spp. in the control of root rot disease of soybean

    Directory of Open Access Journals (Sweden)

    Syed Ehteshamul-Haque

    2014-08-01

    Full Text Available Seed treatment of soybean with Bndyrhizobium japonicum, Trichoderma harzianum, T. viride, T. hamatum, T. koningii and T. pseudokoningii significantly controlled the infection of 30-day-old seedlingsby Maerophomina phaseolina, Rhizoctonia solani and Fusarium spp. In 60-day-old plants Trichoderma spp.. and B. japonicum inhibited the grouth of R. solani and Fusarium spp., whereas the use of B. japonicum (TAL-102 with T. harzianum. T. viride, T. koningii and T. pseudokoningii controlled the infection by M. phaseolina. Greater grain yield was recorded when B. japonium (TAI-102 was used with T. hamatum.

  12. Dispersão de diásporos e ecologia morfofuncional de plântulas de espécies de um fragmento de Floresta Atlântica em Dois Irmãos, Recife–PE. Propagule dispersion and morphofunctional seedling ecology of species in an Atlantic Forest fragment in Dois Irmãos, Recife–PE

    Directory of Open Access Journals (Sweden)

    Diogenes José Gusmão COUTINHO

    2012-06-01

    Full Text Available Trabalhos sobre dispersão de frutos e sementes e aspectos morfofuncionais de plântulas podem fornecer informações essenciais no esclarecimento de questões ligadas à sucessão ecológica, além de contribuir nos trabalhos de inventário, conservação e regeneração de ecossistemas naturais, uma vez que contribuem para a compreensão das funções das estruturas morfológicas nos processos de desenvolvimento e estabelecimento das plantas. Diante do exposto, a presente investigação objetivou levantar as síndromes de dispersão e a morfofuncionalidade de plântulas de espécies de fanerógamos de um fragmento de Floresta Atlântica em Dois Irmãos, Recife–PE. O levantamento das espécies e coleta de material fértil foi feito pelo método do caminhamento, entre o período de janeiro de 2008 e agosto de 2011. As espécies foram demarcadas com fitas e acompanhadas quanto à produção de frutos e sementes para determinação da síndrome de dispersão e posterior germinação, visando à obtenção das plântulas. Também foram feitas observações de campo para identificação das sementes germinadas e plântulas encontradas na serrapilheira. A caracterização da síndrome de dispersão e morfofuncionalidade de plântulas foram feitas através de observações em campo e literatura. Foram levantadas 85 espécies, distribuídas em 19 famílias e 60 gêneros. Quanto ao hábito, 63,85% das espécies são árvores, 16,86% são arbustos, 14,45% são trepadeiras e 7,22% são ervas. A síndrome de dispersão mais frequente foi a zoocoria (66,66%, seguida da autocoria (18,84% e anemocoria (13,05%. O padrão de morfofuncionalidade de plântulas predominantes foi o fanerocotiledonar-epígeo com cotilédones do tipo foliáceo, semelhante ao padrão descrito na literatura para as florestas tropicais úmidas não inundáveis. Papers on fruit and seed dispersal and seedling morphofunctional aspects can provide essential information to clarify issues related to ecological succession, besides contributing in the work of inventory, conservation and regeneration of natural ecosystems, since they contribute to understanding the functions of the structures morphological development processes and plant establishment. The present investigation aimed to raise the dispersal syndromes and morphofunctional seedling species phanerogams a fragment of Atlantic Forest in Dois Irmãos, Recife–PE. The survey of species and fertile material collection was done by the method of traversal, between January 2008 and August 2011. The species were marked with ribbons and monitored for the production of fruits and seeds to determine the dispersion syndrome and subsequent germination, aiming to obtain seedlings. Field observations were also made to identify the seeds germinated and seedlings found in the litter. The characterization of dispersal and seedling morphofunctional were made through field observations and literature. Eighty-five species in 60 genera and 19 families were surveyed. Corcerning to the habit, 63.85% of the species are trees, 16.86% are shrubs, 14.45% are climbers and 7.22% are herbs. The the most frequent syndrome of dispersal was zoochory (66.66% followed by autocory (18.84% and anemochory (13.05%. The standard morphofunctional seedling was the predominant phanerocotylar-epigeal with foliaceous cotyledons type, similar to the pattern described in the literature for tropical rainforests not flooded.

  13. 78 FR 42702 - Endangered and Threatened Wildlife and Plants; Establishment of a Nonessential Experimental...

    Science.gov (United States)

    2013-07-17

    ... eggs, propagules, or individuals) of an endangered or threatened species, and before authorizing any... of a species as a result of removal of individuals, eggs, or propagules for introduction elsewhere... environment, Topeka shiner production was greatly enhanced by the introduction of orangespotted sunfish (Cook...

  14. Feeding Choice and the Fate of Organic Materials Consumed by Sesarma Crabs Perisesarma bidens (De Haan When Offered Different Diets

    Directory of Open Access Journals (Sweden)

    Islam S. S. Mchenga

    2010-01-01

    Full Text Available The feeding preference of the sesarmid crab Perisesarma bidens was investigated when offered different diets: Enteromorpha intestinalis (algae, Kandelia obovata leaves, and propagules. Nutritional value of food, its assimilation, and fates were evaluated using a combination approach of the fatty acids (FAs and C/N ratios. When offered a mixed diet, male crabs preferred algae than leaves and/or propagules, while a female preference was equally for leaves and algae but less than propagules. The nutritional value of algae was higher as indicated by low C : N ratios and high ω3/ω6 ratios than leaves and propagules. FAs comparison of tissues and faeces indicated that crabs efficiently assimilate essential fatty acids (EFAs from a given diet in the order of algae greater than leaves and propagules. Despite of sesarmid crabs being a mangrove leaf-eater, E. intestinalis can potentially be important source of nitrogen supplement for P. bidens under mangrove forests.

  15. Tidal events and salt-marsh structure influence black mangrove (Avicennia germinans) recruitment across an ecotone.

    Science.gov (United States)

    Peterson, Jennifer M; Bell, Susan S

    2012-07-01

    Field experiments were conducted at a black mangrove-salt-marsh ecotone in southwest Florida (U.S.A.) to investigate retention of propagules of the black mangrove, Avicennia germinans, by salt-marsh plants as a mechanism of facilitation operating on recruitment success at landward boundaries. Buoyant A. germinans propagules are dispersed by tides, and stranding is required for establishment; therefore, processes that enable stranding should facilitate mangrove recruitment. We expected the physical structure of salt-marsh vegetation to define propagule retention capacity, and we predicted that salt-marsh plants with distinct growth forms would differentially retain propagules. Experimental monoculture plots (1 m2) of salt-marsh plants with different growth forms (Sporobolus virginicus [grass], Sesuvium portulacastrum [succulent forb], and Batis maritima [succulent scrub]) were created, and A. germinans propagules were emplaced into these plots and monitored over time. For comparison, propagules were also placed into natural polyculture plots (1 m2). Polyculture plots contained at least two of the salt-marsh plant taxa selected for monoculture treatments, and S. virginicus was always present within these polyculture plots. Natural polyculture plots retained 59.3% +/- 11.0% (mean +/- SE) of emplaced propagules. Monocultures varied in their propagule retention capacities with plots of S. virginicus retaining on average 65.7% +/- 11.5% of transplanted propagules compared to 7.2% +/- 1.8% by B. maritima and 5.0% +/- 1.9% by S. portulacastrum. Plots containing S. virginicus retained a significantly greater percentage of emplaced propagules relative to the two succulent salt-marsh taxa. Furthermore, propagule entrapment, across all treatments, was strongly correlated with salt-marsh structure (r2 = 0.6253, P = 0.00001), which was estimated using an indirect quantitative metric (lateral obstruction) calculated from digital images of plots. Overall, our findings imply that

  16. Molecular detection of airborne Emergomyces africanus, a thermally dimorphic fungal pathogen, in Cape Town, South Africa.

    Directory of Open Access Journals (Sweden)

    Ilan S Schwartz

    2018-01-01

    Full Text Available Emergomyces africanus is a thermally dimorphic fungus that causes a systemic mycosis in immunocompromised persons in South Africa. Infection is presumed to follow inhalation of airborne propagules. We developed a quantitative PCR protocol able to detect as few as 5 Es. africanus propagules per day. Samples were collected in Cape Town, South Africa over 50 weeks by a Burkard spore trap with an alternate orifice. We detected Es. africanus in air samples from 34 days (10% distributed over 11 weeks. These results suggest environmental exposure to airborne Es. africanus propagules occurs more commonly in endemic areas than previously appreciated.

  17. Molecular detection of airborne Emergomyces africanus, a thermally dimorphic fungal pathogen, in Cape Town, South Africa.

    Science.gov (United States)

    Schwartz, Ilan S; McLoud, Josh D; Berman, Dilys; Botha, Alfred; Lerm, Barbra; Colebunders, Robert; Levetin, Estelle; Kenyon, Chris

    2018-01-01

    Emergomyces africanus is a thermally dimorphic fungus that causes a systemic mycosis in immunocompromised persons in South Africa. Infection is presumed to follow inhalation of airborne propagules. We developed a quantitative PCR protocol able to detect as few as 5 Es. africanus propagules per day. Samples were collected in Cape Town, South Africa over 50 weeks by a Burkard spore trap with an alternate orifice. We detected Es. africanus in air samples from 34 days (10%) distributed over 11 weeks. These results suggest environmental exposure to airborne Es. africanus propagules occurs more commonly in endemic areas than previously appreciated.

  18. Initial requirements for embryogenic calluses initiation in thin cell ...

    African Journals Online (AJOL)

    Administrator

    2011-09-12

    Sep 12, 2011 ... Generating power using alternative models via the production of biodiesel ... advantage that it is induced from different types of explants (propagules) ..... with thickened walls in a spiral form (Figure 1f). Accor- ding to Guerra ...

  19. Genetic structure of Potentilla acaulis (Rosaceae) populations ...

    African Journals Online (AJOL)

    Jane

    2011-07-18

    Jul 18, 2011 ... populations based on randomly amplified polymorphic. DNA (RAPD) in habitat ..... the correlation between ΦST values and genetic distances was highly ... Propagule recruitment from genets of perennial clonal plants could ...

  20. Genetic diversity and antifungal susceptibility profiles in causative agents of sporotrichosis

    NARCIS (Netherlands)

    Rodrigues, Anderson Messias; de Hoog, G Sybren; de Cássia Pires, Débora; Brihante, Raimunda Sâmia Nogueira; Sidrim, José Júlio da Costa; Gadelha, Marcos Fabio; Colombo, Arnaldo Lopes; de Camargo, Zoilo Pires

    2014-01-01

    BACKGROUND: Sporotrichosis is a chronic subcutaneous mycosis of humans and animals, which is typically acquired by traumatic inoculation of plant material contaminated with Sporothrix propagules, or via animals, mainly felines. Sporothrix infections notably occur in outbreaks, with large epidemics

  1. Genetic diversity and antifungal susceptibility profiles in agents of sporotrichosis

    NARCIS (Netherlands)

    Messias Rodrigues, A.; de Hoog, G.S.; de Cássia Pires, D.; Nogueira Brihante, R.S.; da Costa Sidrim, J.J.; Gadelha, M.F.; Lopes Colombo, A.; Pires de Camargo, Z.

    2014-01-01

    Background: Sporotrichosis is a chronic subcutaneous mycosis of humans and animals, which is typically acquired by traumatic inoculation of plant material contaminated with Sporothrix propagules, or via animals, mainly felines. Sporothrix infections notably occur in outbreaks, with large epidemics

  2. The Aquatic Macrophyte Seed Bank in Lake Onalaska, Wisconsin

    National Research Council Canada - National Science Library

    McFarland, D

    1998-01-01

    .... americana have made a partial recovery. While the production of vegetative propagules may largely account for increases in populations of both species, the extent to which seed production may contribute to their expansion in the lake is unknown...

  3. Propagation Techniques for Highland Bamboo (Arundinaria alpina ...

    African Journals Online (AJOL)

    1Ethiopian Institute of Agricultural Research, Forestry Research Center, ... (10 new shoots per propagule), along its stem length (at the upper, middle and butt ... laminated bamboo lumber (LBL), oriented strand board (OSB), medium density ...

  4. Mangrove Restoration Areas in Salt River Bay National Historical Park and Ecological Preserve

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Apart from two 100 m test plots, mangrove restoration activities were conducted between 1999 and 2001. Each year, thousands of red mangrove propagules were planted...

  5. Detection of somaclonal variation in micropropagated Hibiscus ...

    African Journals Online (AJOL)

    User

    Paper Accepted on 26 July 2010. Abstract. The main ... micropropagated propagules of ornamental pineapple (Santos et al., 2008) and in cucumber ... fleshy calyces are used for wine making, juice, jam, jelly, syrup, gelatin, pudding, ice cream ...

  6. Bistable dynamics of an insect–pathogen model

    Indian Academy of Sciences (India)

    acterize diseases that spread through environmental propagules or through random contact ... This fact motivated us to investigate the effects of cost of disease resistance .... Therefore, the model may have complex dynamic behaviour depen-.

  7. Antimicrobial screening of some medicinal plants of Pakistan

    International Nuclear Information System (INIS)

    Jahan, N.; Ahmad, M.; Zia-ul-Haq, M.; Qureshi, M.; Mehjabeen; Alam, S.M.J.

    2010-01-01

    Methanolic extracts of Thuja occidentalis, Vernonia anthelmintica, Dryopteris chrysocoma and Trachyspermum ammi were tested In vitro for their antibacterial and antifungal activities. Antibacterial study performed against six bacteria viz., Escherichia coli, Citrobacter, Shigella flexenari, Yersinia aldovae, Staphylococcus aureus and Pseudomonas aeruginosa indicated that has potent activity against all microorganisms. The antifungal activity of these extracts was performed against six fungi, viz., Saccharomyces cereviciae, Aspergillus parasiticus, Trichophyton rubrum, Macrophomina, Fusarium solani and Candida albicans. The extracts showed significant results against different fungal strains. (author)

  8. Sheared-root inocula of vesicular-arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Sylvia, D M; Jarstfer, A G

    1992-01-01

    For efficient handling, vesicular-arbuscular mycorrhizal fungi should be processed into small and uniform inocula; however, processing can reduce the inoculum density. In this article we describe the preparation and use of sheared-root inocula of Glomus spp. in which inoculum densities were increased during processing. Our objectives were to determine inoculum viability and density after shearing and to ascertain if the sheared inocula could be pelletized or used with a gel carrier. Root samples were harvested from aeroponic cultures, blotted dry, cut into 1-cm lengths, and sheared in a food processor for up to 80 s. After shearing, the inoculum was washed over sieves, and the propagule density in each fraction was determined. Sheared inocula were also encapsulated in carrageenan or used in a gel carrier. Shearing aeroponically produced root inocula reduced particle size. Propagule density increased with decreasing size fraction down to a size of 63 mum, after which propagule density decreased. The weighted-average propagule density of the inoculum was 135,380 propagules g (dry weight) of sheared root material. Sheared roots were encapsulated successfully in carrageenan, and the gel served as an effective carrier. Aeroponic root inoculum was stored dry at 4 degrees C for 23 months without significant reduction in propagule density; however, this material was not appropriate for shearing. Moist roots, useful for shearing, began to lose propagule density after 1 month of storage. Shearing proved to be an excellent method to prepare viable root inocula of small and uniform size, allowing for more efficient and effective use of limited inoculum supplies.

  9. Infection Unit Density as an Index of Infection Potential of Arbuscular Mycorrhizal Fungi.

    Science.gov (United States)

    Ohtomo, Ryo; Kobae, Yoshihiro; Morimoto, Sho; Oka, Norikuni

    2018-03-29

    The effective use of arbuscular mycorrhizal (AM) fungal function to promote host plant phosphate uptake in agricultural practice requires the accurate quantitative evaluation of AM fungal infection potential in field soil or AM fungal inoculation material. The number of infection units (IUs), intraradical fungal structures derived from single root entries formed after a short cultivation period, may reflect the number of propagules in soil when pot soil is completely permeated by the host root. However, the original IU method, in which all AM propagules in a pot are counted, requires the fine tuning of plant growing conditions and is considered to be laborious. The objective of the present study was to test whether IU density, not the total count of IU, but the number of IUs per unit root length, reflects the density of AM fungal propagules in soil. IU density assessed after 12 d of host plant cultivation and 3,3'-diaminobenzidine (DAB) staining showed a stronger linear correlation with propagule density than the mean infection percentage (MIP). In addition, IU density was affected less by the host plant species than MIP. We suggest that IU density provides a more rapid and reliable quantitation of the propagule density of AM fungi than MIP or the original IU method. Thus, IU density may be a more robust index of AM fungal infection potential for research and practical applications.

  10. Enhancement of local species richness in tundra by seed dispersal through guts of muskox and barnacle goose

    DEFF Research Database (Denmark)

    Bruun, Hans Henrik; Lundgren, Rebekka; Philipp, Marianne

    2008-01-01

    The potential contribution of vertebrate-mediated seed rain to the maintenance of plant community richness in a High Arctic ecosystem was investigated. We analyzed viable seed content in dung of the four numerically most important terrestrial vertebrates in Northeast Greenland - muskox (Ovibos...... moschatus), barnacle goose (Branta leucopsis), Arctic fox (Alopex lagopus) and Arctic hare (Lepus arcticus). High numbers of plant propagules were found in the dung of muskox and barnacle goose. Seeds of many plant species were found in the faeces of one vertebrate species only. Propagule composition...... in barnacle goose droppings was relatively uniform over samples, with a high abundance of the nutritious bulbils of Polygonum viviparum (Bistorta vivipara), suggesting that geese have a narrow habitat preference and feed selectively. Propagule composition in muskox dung was diverse and heterogeneous among...

  11. Vegetative propagation of Bambusa vulgaris

    Directory of Open Access Journals (Sweden)

    Rafael Malfitano Braga

    2017-06-01

    Full Text Available Bamboo is an important source of raw material of multiple uses. The development of simple techniques for its propagation is a practical way to enable its implementation in ownership of low technology. The present work had the objective of evaluating artisanal propagation methods for Bambusa vulgaris. Two types of propagules were tested, with buds budded or not, and three relative positions to the removal of vegetative material on the culm. The best propagule was with only one node, extracted from the lower thirds of the stem, presenting 72% of rooting. This result demonstrates its potential for seedling production of this species under low tech.

  12. Antimicrobial screening of some plants of medicinal importance

    International Nuclear Information System (INIS)

    Mehjabeen, A.; Ahmad, M.; Zia-ul-Haq, M.; Wazir, A.; Jahan, N.

    2011-01-01

    Methanolic extracts of Solanum nigrum (leaves and seeds of both black and red varieties), Elettaria cardamomum Cuscuta reflexa and Cinnamomum camphora were tested in vitro for their antibacterial and antifungal activities. Antibacterial study performed against six bacteria viz., Escherichia coli, Citrobacter, Shigella flexenari, Staphylococcus aureus, Pseudomonas aeruginosa and Yersinia aldovae indicated that investigated plants have potent activity against all microorganisms. The antifungal activity of these extracts was performed against six fungi, viz., Saccharomyces cereviciae, Aspergillus parasiticus, Trichophyton rubrum, Macrophomina, Fusarium solani and Candida albicans. The extracts showed moderate as well as significant activity against different fungal strains. (author)

  13. Germination of Phytophthora ramorum chlamydospores: a comparison of separation method and chlamydospore age

    Science.gov (United States)

    Justin P. Shaffer; Jennifer L. Parke

    2013-01-01

    Phytophthora ramorum characteristically produces large amounts of chlamydospores in vitro, but the role of these propagules in the disease cycle remains unclear. Germination is difficult to observe and quantify if chlamydospores are not free of mycelium, and the low frequency of germination commonly reported suggests that...

  14. f Path fumos isola hogeni sorosea ates ag icity an a (=Pa gainst l ...

    African Journals Online (AJOL)

    sunny

    on the insects' cuticle and to penetrate it, to its production of secondary ... through IR and NMR, which provide concrete idea of a particular domain ..... nd Rodriguez n be explained maining period ost insects to ge. The speed on propagule a positive cor ores and mor u et al., 1989 all areas of the penetration by tt and Goette.

  15. A decrease in bulk water and mannitol and accumulation of trehalose and trehalose-based oligosaccharides define a two-stage maturation process towards extreme stress resistance in ascospores of Neosartorya fischeri (Aspergillus fischeri)

    NARCIS (Netherlands)

    Wyatt, Timon T; Golovina, Elena A; van Leeuwen, Richard; Hallsworth, John E; Wösten, Han A B; Dijksterhuis, Jan

    Fungal propagules survive stresses better than vegetative cells. Neosartorya fischeri, an Aspergillus teleomorph, forms ascospores that survive high temperatures or drying followed by heat. Not much is known about maturation and development of extreme stress resistance in fungal cells. This study

  16. High-temperature treatment for efficient drying of bread rye and reduction of fungal contaminants

    DEFF Research Database (Denmark)

    Kristensen, E.F.; Elmholt, S.; Thrane, Ulf

    2005-01-01

    time of 10(.)5 min and a temperature of 64 degrees C killed 99% of the yeast propagules and 98% of the filamentous fungi. Moisture contents were reduced to about 12%. A similar drying regime in a supplementary trial reduced the number of P. verrucosum contaminated kernels from more than 70% to 12...

  17. Survival and chlamydospore production of Phytophthora ramorum in California bay laurel leaves

    Science.gov (United States)

    E. Fichtner; D. Rizzo; S. Lynch; D. Rizzo; G. Buckles; J. Parke

    2009-01-01

    Sudden oak death manifests as non-lethal foliar lesions on bay laurel (Umbellularia californica), which support sporulation and survival of Phytophthora ramorum in forest ecosystems. The pathogen survives the dry summers in a proportion of attached bay leaves, but the propagules responsible for survival are...

  18. Astroturf seed traps for studying hydrochory

    NARCIS (Netherlands)

    Wolters, M; Geertsema, J; Chang, ER; Veeneklaas, RM; Carey, PD; Bakker, JP

    1. Astroturf mats can effectively trap diaspores dispersed by tidal water. 2. Within four tidal inundations, up to 745 propagules per m(2) and between three and eight different species per astroturf mat were trapped. Overall, 15 different species were collected on the astroturf mats, 10 of which

  19. Lindernia dubia (L.) Pennell

    Czech Academy of Sciences Publication Activity Database

    Šumberová, Kateřina; Juříček, M.; Paulič, R.

    2016-01-01

    Roč. 51, č. 1 (2016), s. 104-107 ISSN 1211-5258 R&D Projects: GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : plant propagule dispersal * wetlands * plant invasions Subject RIV: EF - Botanics

  20. Biological control of aflatoxin production in corn using non-aflatoxigenic Aspergillus flavus administered as a bioplastic-based seed coating

    Science.gov (United States)

    Since its first introduction in the early 1990s, tremendous progress has been made in the application of biocontrol techniques for reducing aflatoxin contamination in corn. In almost three decades, the basic concept has remained centered on massive application of propagules of non-aflatoxigenic A. f...

  1. Emerging sporotrichosis driven by clonal and recombinant Sporothrix species

    NARCIS (Netherlands)

    Rodrigues, A.M.; de Hoog, G.S.; Zhang, Y.; Pires de Camargo, Z.

    2014-01-01

    Sporotrichosis, caused by agents of the fungal genus Sporothrix, occurs worldwide, but the infectious species are not evenly distributed. Sporothrix propagules usually gain entry into the warm-blooded host through minor trauma to the skin from contaminated plant debris or through scratches or bites

  2. Effect of N-fertilizer rates on Dry Matter Yield (DMY) and quality of ...

    African Journals Online (AJOL)

    Effect of N-fertilizer rates on Dry Matter Yield (DMY) and quality of pinapple propagules (Ananas comosus) in the acid sands of cross river. W Ubi, M W Ubi, VE Osedeke. Abstract. No Abstract. Global Journal of Pure and Applied Physics Vol. 14 (1) 2008 pp. 1-4. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD ...

  3. Pythium insidiosum: An overview

    NARCIS (Netherlands)

    Gaastra, W.; Lipman, L.J.A.; De Cock, A.W.; Exel, T.K.; Pegge, R.B.; Scheurwater, J.; Vilela, R.; Mendoza, L.

    2010-01-01

    Pythium insidiosum is an oomycete pathogenic in mammals. The infection occurs mainly in tropical and subtropical areas, particularly in horses, dogs and humans. Infection is acquired through small wounds via contact with water that contains motile zoospores or other propagules (zoospores or hyphae).

  4. Hardy–Weinberg Equilibrium and the Foundations of Evolutionary ...

    Indian Academy of Sciences (India)

    propagules such as pollen) can both be assumed to alter the allele frequency in the gamete ... of organisms interact to give rise to evolutionary change which is then manifested as the diversity of living forms we marvel at. We will undertake ...

  5. The role of animal seed dispersal in accelerating native forest regeneration on degraded tropical lands.

    Science.gov (United States)

    J.M. Wunderle Jr.

    1997-01-01

    this paper reviews the characteristicas of animal seed dispersal. relevant to tropical forest restoration efforts and discusses their managment implication. In many tropical regions seed dispersal by animals is the predominant form of dissemination of propagules and has a potential to facilitate recolonization of native vegetation on degraded sites.

  6. Effect Of Culture Media On The Plant Growth And Establishment Of ...

    African Journals Online (AJOL)

    An experiment was conducted to assess the regeneration of vegetative propagule of Myrianthus arboreous in different growing media. The objective of this study was to assess the response of stem cuttings to different culture media for plant take and survival. The growth variables taken increase with time. Topsoil produced ...

  7. Presence of Fusarium spp. in air and soil associated with sorghum fields

    Science.gov (United States)

    Sorghum grain, valuable for feed, food and bioenergy, can be colonized by several Fusarium species; therefore, it was of interest to identify possible sources of conidia. Analysis of air and soil samples provided evidence for the presence of propagules from Fusarium genotypes that may cause grain in...

  8. Relative susceptibility of Musa genotypes to banana bunchy top disease in Cameroon and implication for disease management

    Science.gov (United States)

    Banana bunchy top disease (BBTD) is a serious threat to banana and plantain (Musa spp.) production. BBTD is caused by the Banana bunchy top virus (BBTV, genus Babuvirus) which is spread through infected plant propagules and banana aphid, Pentalonia nigronervosa. A high level of resistance to BBTD in...

  9. Book review: Bayesian analysis for population ecology

    Science.gov (United States)

    Link, William A.

    2011-01-01

    Brian Dennis described the field of ecology as “fertile, uncolonized ground for Bayesian ideas.” He continued: “The Bayesian propagule has arrived at the shore. Ecologists need to think long and hard about the consequences of a Bayesian ecology. The Bayesian outlook is a successful competitor, but is it a weed? I think so.” (Dennis 2004)

  10. escape and naturalization of tagetes patula in western ethiopia

    African Journals Online (AJOL)

    preferred customer

    Key Words /Phrases: Fire, invasive species, propagules, soil seed bank. * Author to whom ... because of increased road development. The spread of .... placed in a thermo-regulated greenhouse with an average ... germinated when the radicle penetrated the seed coat. Germination was recorded daily in the first two weeks ...

  11. Effect of arbuscular mycorrhizal fungi on onion growth and onion stunting caused by Rhizoctonia solani, 2013.

    Science.gov (United States)

    A preliminary study was conducted in a greenhouse (15 ± 1oC, with supplemental lights for 12 h/day) to determine the role of AMF on onion growth and for reducing the severity of onion stunting, using a commercial AMF inoculant, BioTerra Plus, that contains 104 propagules/g (ppg) of Glomus intraradic...

  12. 78 FR 7890 - Endangered and Threatened Wildlife and Plants; Establishment of a Nonessential Experimental...

    Science.gov (United States)

    2013-02-04

    ... experimental population (including eggs, propagules, or individuals) of an endangered or threatened species... possible adverse effects on extant populations of a species as a result of removal of individuals, eggs, or...; Tomasik and Cook 2005, p. 390; Cegelski et al. 2006, p. 206; Aubry et al. 2011, pp. 21-22; Inman et al...

  13. 78 FR 4813 - Endangered and Threatened Wildlife and Plants; Establishment of a Nonessential Experimental...

    Science.gov (United States)

    2013-01-23

    .... Before authorizing the release as an experimental population of any population (including eggs... removal of individuals, eggs, or propagules for introduction elsewhere; (2) the likelihood that any such... introduction of orangespotted sunfish (Cook 2011, pers. comm.). Topeka shiners feed primarily on insects, such...

  14. Lantana camara L. (Verbenaceae) invasion along streams in a ...

    Indian Academy of Sciences (India)

    Streams are periodically disturbed due to flooding, act as edges between habitats and also facilitate the dispersal of propagules, thus being potentially more vulnerable to invasions than adjoining regions. We used a landscape-wide transect-based sampling strategy and a mixed effects modelling approach to understand ...

  15. Landscape genetics and limiting factors

    Science.gov (United States)

    Samuel A. Cushman; Andrew J. Shirk; Erin L. Landguth

    2013-01-01

    Population connectivity is mediated by the movement of organisms or propagules through landscapes. However, little is known about how variation in the pattern of landscape mosaics affects the detectability of landscape genetic relationships. The goal of this paper is to explore the impacts of limiting factors on landscape genetic processes using simulation...

  16. Effects of experimental snowmelt and rain on dispersal of six plant species

    NARCIS (Netherlands)

    Sarneel, J. M.

    2016-01-01

    Water flows affect dispersal of propagules of many plant species, and rivers and streams are therefore very important dispersal vectors. However, small water flows such as trough rain and snowmelt are much more common, but their effects on dispersal are barely studied. The importance of this form of

  17. Invasion success in Cogongrass (Imperata cylindrica): A population genetic approach exploring genetic diversity and historical introductions

    Science.gov (United States)

    Rima D. Lucardi; Lisa E. Wallace; Gary N. Ervin

    2014-01-01

    Propagule pressure significantly contributes to and limits the potential success of a biological invasion, especially during transport, introduction, and establishment. Events such as multiple introductions of foreign parent material and gene flow among them can increase genetic diversity in founding populations, often leading to greater invasion success. We applied...

  18. Consistent association of fungus Fusarium mangiferae Britz with ...

    African Journals Online (AJOL)

    In exotic ones, maximum and minimum infections of 97.33 and 70.67% were noted in the cultivars Sensation and Pop, respectively. Light and transmission electron microscopy proved helpful in investigating the morphological matrix and ultrastructure of the propagules of fungus F. mangiferae. Key words: Mangifera indica, ...

  19. Strategies for Seed Propagation of Native Forbs

    Science.gov (United States)

    Susan E. Meyer

    2006-01-01

    Native forbs are an increasingly important component of container production for many public and private nurseries. Propagators are often called upon to grow species with unknown requirements. A systematic approach is required to obtain plants from seeds of these species, beginning with determining what is a propagule and evaluating seed quality. Next, seed dormancy...

  20. Development of loop-mediated isothermal amplification and SYBR green real-time PCR methods for the detection of Citrus yellow mosaic badnavirus in citrus species.

    Science.gov (United States)

    Anthony Johnson, A M; Dasgupta, I; Sai Gopal, D V R

    2014-07-01

    Citrus yellow mosaic badnavirus (CMBV) is an important pathogen in southern India spread by infected citrus propagules. One of the measures to arrest the spread of CMBV is to develop methods to screen and certify citrus propagules as CMBV-free. The methods loop-mediated isothermal amplification (LAMP) and SYBR green real-time PCR (SGRTPCR) have been developed for the efficient detection of CMBV in citrus propagules. This paper compares the sensitivities of LAMP and SGRTPCR with polymerase chain reaction (PCR) for the detection of CMBV. Whereas PCR and LAMP were able to detect CMBV from a minimum of 10 ng of total DNA of infected leaf samples, SGRTPCR could detect the same from 1 ng of total DNA. Using SGRTPCR, the viral titres were estimated to be the highest in rough lemon and lowest in Nagpur Mandarin of the five naturally infected citrus species tested. The results will help in designing suitable strategies for the sensitive detection of CMBV from citrus propagules. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Food for thought: risks of non-native species transfer to Antarctica with fresh produce

    NARCIS (Netherlands)

    Hughes, K.A.; Lee, J.E.; Tsujimoto, M.; Imura, S.; Bergstrom, D.M.; Ware, C.; Lebouvier, M.; Huiskes, A.H.L.; Gremmen, N.J.M.; Frenot, Y.; Bridge, P.D.; Chown, S.L.

    2011-01-01

    To understand fully the risk of biological invasions, it is necessary to quantify propagule pressure along all introduction pathways. In the Antarctic region, importation of fresh produce is a potentially high risk, but as yet unquantified pathway. To address this knowledge gap, >11,250 fruit and

  2. Transcriptome of Aspergillus flavus aswA (AFLA_085170) deletion strain related to sclerotial development and production of secondary metabolites

    Science.gov (United States)

    Aspergillus flavus produces many secondary metabolites including aflatoxins. Besides conidia, the fungus uses sclerotia as another type of propagule. We obtained transcriptomes from four growth conditions of the aswA mutant, a strain impaired in sclerotial development and production of sclerotium-sp...

  3. Local-scale invasion pathways and small founder numbers in introduced Sacramento pikeminnow (Ptychocheilus grandis)

    Science.gov (United States)

    Andrew P. Kinziger; Rodney J. Nakamoto; Bret C. Harvey

    2014-01-01

    Given the general pattern of invasions with severe ecological consequences commonly resulting from multiple introductions of large numbers of individuals on the intercontinental scale, we explored an example of a highly successful, ecologically significant invader introduced over a short distance, possibly via minimal propagule pressure. The Sacramento pikeminnow (

  4. Prunus serotina unleashed: invader dominance after 70 years of forest development

    NARCIS (Netherlands)

    Vanhellemont, M.; Wauters, L.; Baeten, L.; Bijlsma, R.J.; Frenne, De P.; Hermy, M.; Verheyen, K.

    2010-01-01

    Propagule pressure and disturbance have both been found to facilitate invasion. Therefore, knowledge on the history of introduction and disturbance is vital for understanding an invasion process, and research should focus on areas in which the invasive species has not been deliberately introduced or

  5. How does surrounding vegetation affect the course of succession: A five-year container experiment

    Czech Academy of Sciences Publication Activity Database

    Lanta, Vojtěch; Lepš, Jan

    2009-01-01

    Roč. 20, č. 4 (2009), s. 686-694 ISSN 1100-9233 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z50070508 Keywords : Convergence * Habitat effect * Propagule availability Subject RIV: EF - Botanics Impact factor: 2.376, year: 2009

  6. Green Fluorescent Protein (GFP) as a reporter gene for the plant pathogenic oomycete Phytophthora ramorum

    Science.gov (United States)

    Marko Riedel; Gautier Calmin; Lassaad Belbahri; Francois Lefort; Monika Gotz; Stefan Wagner; Sabine. Werres

    2009-01-01

    Transgenic Phytophthora ramorum strains that produce green fluorescent protein (GFP) constitutively were obtained after stable DNA integration using a polyethylene glycol and CaCl2-based transformation protocol. Green fluorescent protein production was studied in developing colonies and in different propagules of the pathogen...

  7. Omezení a evoluce velikosti vajec a mláďat u amniotických obratlovců

    OpenAIRE

    Kubát, Jan

    2011-01-01

    Amniotes (mammals, reptiles including birds) exhibit wide diversity in egg/offspring size relatively to female body size. This study reviews mechanisms determining size of propagules (such as morphological or physiological constraints, trade-off between size versus number etc.). Particular attention is paid to comparison of allometric relationship in egg/offspring size among individual amniotic lineages.

  8. Induced mutation in the improvement of beans

    International Nuclear Information System (INIS)

    Avila, R.L.; Murty, B.R.

    1984-01-01

    A program on mutational rectification was undertaken in 1978 utilizing gamma radiation, as seed treatment for three local cultivars of compea, Vigna unguiculata plus one cultivar of mungbean, Vigna radiata. The selection criteria were compact plant type with determinate habit, early maturity, resistance to Macrophomina and high yield. The selected material now in M 7 generation, selection being made in M 2 for plant type. In subsequent generations selections were made for resistance to Macrophomina, stability of plant type, uniform pod filling, seed size, good nodulation, synchronous flowering and productivity under close spacing conditions. Simultaneous studies on root development were made at seedling stage. In mungbean, emphasis on non-shattering was made. Finally 12 mutants were selected in M 5 , with uniformity for the cited characters and higher yields than the parental material, ranging from 20 to 110% superior yield in some mutants and sowing dates. Multilocation trials are being conducted to test the wide adaptability of these mutants. Chemical mutagenesis using sodium azide with and without gamma radiation was also used. From these trials nonnodulating mutants were recovered. These materials are being multiplied to be used in basic studies of the Rhizobium - legume symbiosis. Ecophysiological studies of the promising mutants have been carried out under different sowing dates at 45 day intervals. These results are of wide interest in studies of tropical adaptation of grain legumes, on which very few reports are available so far. These results are discussed with particular reference to yield and its stability for the cropping system in Venezuela. (author)

  9. Potentiel infectieux des sols de cultures de tomate (Lycopersicon esculentum Mill. sous abri et incidence de l'âge de repiquage sur la vigueur des plants vis-à-vis de Pythium sp. à Songon-Dabou en Côte d'Ivoire

    Directory of Open Access Journals (Sweden)

    Koné, D.

    2008-01-01

    Full Text Available Potentiel Infectious of Soils Fields of Tomato (Lycopersicon esculentum Mill. in Greenhouse and the Age Incidence Facing Pythium sp. on the Plants at Songon-Dabou in Ivory Coast. Songon-Dabou area represents one of the spheres activities of tomato in Ivory Coast. The production of tomato is strongly influenced by some of viruses, bacteria and soil born fungi. A study was conducted on the soils of different fields with three varieties of tomato (Caraïbo, Mongal and Tropimech to identify the most susceptible variety to soil born fungi at Songon-Dabou. By baiting with 20 days old seedlings, 4 genus fungi of Pythium, Fusarium, Sclerotium and Macrophomina have been isolated. Pythium sp. presented the greatest attack (32% while Macrophomina phaseoli was isolated for the first time on market gardening in Ivory Coast. Tomato plants have been inoculated by Pythium at different stages obtained from seedling to 25 days old nursery seedlings. That experiment was repeated three times. This work was conducted in greenhouse during 26 days after transplantation of the plants in the pots. These results confirm that Pythium sp. is a fungus of damping off (100% and that age of transplantation reduces the rate of mortality (less than 20%.

  10. Screening of Azotobacter isolates for PGP properties and antifungal activity

    Directory of Open Access Journals (Sweden)

    Bjelić Dragana Đ.

    2015-01-01

    Full Text Available Аmong 50 bacterial isolates obtained from maize rhizospherе, 13 isolates belonged to the genus Azotobacter. Isolates were biochemically characterized and estimated for pH and halo tolerance ability and antibiotic resistance. According to characterization, the six representative isolates were selected and further screened in vitro for plant growth promoting properties: production of indole-3-acetic acid (IAA, siderophores, hydrogen cyanide (HCN, exopolysaccharides, phosphate solubilization and antifungal activity (vs. Helminthosporium sp., Macrophomina sp., Fusarium sp.. Beside HCN production, PGP properties were detected for all isolates except Azt7. All isolates produced IAA in the medium without L-tryptophan and the amount of produced IAA increased with concentration of precursor in medium. The highest amount of IAA was produced by isolates Azt4 (37.69 and 45.86 μg ml-1 and Azt5 (29.44 and 50.38 μg ml-1 in the medium with addition of L-tryptophan (2.5 and 5 mM. The isolates showed the highest antifungal activity against Helminthosporium sp. and the smallest antagonistic effect on Macrophomina sp. Radial Growth Inhibition (RGI obtained by the confrontation of isolates with tested phytopathogenic fungi, ranged from 10 to 48%. [Projekat Ministarstva nauke Republike Srbije, br. TR 31073

  11. Increased levels of airborne fungal spores to Populus tremuloides grown under elevated atmospheric CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Klinoromos, J. N. [Guelph Univ., ON (Canada). Dept. of Botany; Rillig, M. C.; Allen, M. F. [San Diego State Univ., CA (United States). Dept. of Biology; Zak, D. R. [Michigan Univ., Ann Arbor, MI (United States). School of Natural Resources and Environment; Pregitzer, K. S.; Kubiske, M. E. [Michigan Technological Univ., Houghton, MI (United States). School of Forestry and Wood Products

    1997-10-01

    The objective of this study was to test the hypothesis that soil fungi sporulation would be facilitated by increase levels of CO{sub 2} concentration, leading to higher concentrations of fungal population in the atmosphere. Results showed that airborne fungal propagules were increased fourfold under twice-ambient CO{sub 2} concentration, and the decomposing leaf litter, the main source of fungal propagules, produced a fivefold increase of spores under elevated CO{sub 2} conditions. These results confirm the hypothesis that CO{sub 2} concentrations have a direct effect on microbial functions, which in turn will affect decomposition and plant pathogen dynamics. Since there is increasing evidence for causal relationship and exposure to aeroallergens and development of asthma in humans, there is a compelling need to study fungal epidemiology in the context of a globally changing environment. 28 refs., 3 figs.

  12. Dispersal and colonisation of plants in lowland streams: success rates and bottlenecks

    DEFF Research Database (Denmark)

    Riis, Tenna

    2008-01-01

    -rich lowland streams. Rather, I conclude that primary colonisation is the main constraint to regaining vegetation in lowland streams in general and in vegetation-free rehabilitated streams in particular. Therefore, if plant colonisation is a target for stream rehabilitation, it is important to enhance......Plant dispersal and colonisation, including rates of dispersal, retention, colonisation and survival of dispersed propagules (shoots and seeds), were studied in a 300-m stream reach in a macrophyte-rich lowland stream during one growing season. Relationships between colonisation processes...... and simple flow parameters were tested. Each fortnight during a growing season, the number of dispersed plant propagules and the number of new and lost plant colonisations since the last sampling day were recorded. The retention of dispersing shoots was tested on two occasions during the growing season...

  13. Experimental evolution of an alternating uni- and multicellular life cycle in Chlamydomonas reinhardtii

    Science.gov (United States)

    Ratcliff, William C.; Herron, Matthew D.; Howell, Kathryn; Pentz, Jennifer T.; Rosenzweig, Frank; Travisano, Michael

    2013-01-01

    The transition to multicellularity enabled the evolution of large, complex organisms, but early steps in this transition remain poorly understood. Here we show that multicellular complexity, including development from a single cell, can evolve rapidly in a unicellular organism that has never had a multicellular ancestor. We subject the alga Chlamydomonas reinhardtii to conditions that favour multicellularity, resulting in the evolution of a multicellular life cycle in which clusters reproduce via motile unicellular propagules. While a single-cell genetic bottleneck during ontogeny is widely regarded as an adaptation to limit among-cell conflict, its appearance very early in this transition suggests that it did not evolve for this purpose. Instead, we find that unicellular propagules are adaptive even in the absence of intercellular conflict, maximizing cluster-level fecundity. These results demonstrate that the unicellular bottleneck, a trait essential for evolving multicellular complexity, can arise rapidly via co-option of the ancestral unicellular form. PMID:24193369

  14. Naturalization and impact of a horticultural species, Cotoneaster horizontalis (Rosaceae) in biodiversity hotspots in Belgium

    OpenAIRE

    Piqueray, Julien; Mahy, Grégory; Vanderhoeven, Sonia

    2008-01-01

    Cultivation of ornamental plant species has been recognized to foster plant naturalization of exotics by counteracting environmental stochasticity and continuously providing propagules. As a preliminary attempt to describe the invasion status of C horizontalis, we gathered information on the occurrence of the species in Belgium by compiling various databases. We assessed the naturalization status of C. horizontalis in Belgian calcareous grasslands, high-value habitats recognized as biodiversi...

  15. Growing Industries, Growing Invasions? The Case of the Argentine Ant in Vineyards of Northern Argentina

    OpenAIRE

    Maria Schulze-Sylvester; José A. Corronca; Carolina I. Paris

    2018-01-01

    The invasive Argentine ant causes ecological and economic damage worldwide. In 2011, this species was reported in vineyards of Cafayate, a wine-producing town in the Andes, Argentina. While the local xeric climate is unsuitable for Argentine ants, populations could establish in association with vineyards where human activity and irrigation facilitate propagule introduction and survival. In 2013–2014, we combined extensive sampling of the area using ant-baits with monitoring of the change in l...

  16. Assemblage structure: an overlooked component of human-mediated species movements among freshwater ecosystems

    Directory of Open Access Journals (Sweden)

    D. Andrew R. Drake

    2014-04-01

    Full Text Available The spread and impact of alien species among freshwater ecosystems has increased with global trade and human movement; therefore, quantifying the role of anthropogenic and ecological factors that increase the risk of invasion is an important conservation goal. Two factors considered as null models when assessing the potential for invasion are colonization pressure (i.e., the number of species introduced and propagule pressure [i.e., the number (propagule size, and frequency (propagule number, of individuals of each species introduced]. We translate the terminology of species abundance distributions to the invasion terminology of propagule size and colonization size (PS and CS, respectively. We conduct hypothesis testing to determine the underlying statistical species abundance distribution for zooplankton assemblages transported between freshwater ecosystems; and, on the basis of a lognormal distribution, construct four hypothetical assemblages spanning assemblage structure, rank-abundance gradient (e.g., even vs uneven, total abundance (of all species combined, and relative contribution of PS vs CS. For a given CS, many combinations of PS and total abundance can occur when transported assemblages conform to a lognormal species abundance distribution; therefore, for a given transportation event, many combinations of CS and PS are possible with potentially different ecological outcomes. An assemblage exhibiting high PS but low CS (species poor, but highly abundant may overcome demographic barriers to establishment, but with lower certainty of amenable environmental conditions in the recipient region; whereas, the opposite extreme, high CS and low PS (species rich, but low abundance per species may provide multiple opportunities for one of n arriving species to circumvent environmental barriers, albeit with lower potential to overcome demographic constraints. Species abundance distributions and the corresponding influence of CS and PS are some of

  17. Sphagnum farming in Germany – a review of progress

    OpenAIRE

    G. Gaudig; F. Fengler; M. Krebs; A. Prager; J. Schulz; S. Wichmann; H. Joosten

    2014-01-01

    In ombrotrophic, nutrient-poor peatlands, the cultivation of peatmoss (Sphagnum spp.) is a promising paludiculture option. Since 2001 we have been studying peatmoss cultivation (‘Sphagnum farming’) in greenhouse and field experiments, paying special attention to propagation, propagule storage, establishment, productivity and regeneration. Our studies show that Sphagnum farming in Germany may provide a sustainable high-quality alternative to fossil white peat as a raw material for horticultural...

  18. Assessment of mycorrhizal colonisation and soil nutrients in unmanaged fire-impacted soils from two target restoration sites

    Energy Technology Data Exchange (ETDEWEB)

    Dias, J. M.; Oliveira, R. S.; Franco, A. R.; Ritz, K.; Nunan, N.; Castro, P. M. L.

    2010-07-01

    The mycorrhizal colonisation of plants grown in unmanaged soils from two restoration sites with a fire history in Northern Portugal was evaluated from the perspective of supporting restoration programmes. To promote restoration of original tree stands, Quercus ilex L. and Pinus pinaster Ait. were used as target species on two sites, denoted Site 1 and 2 respectively. The aim of the study was to assess whether mycorrhizal propagules that survived fire episodes could serve as in situ inoculum sources, and to analyse the spatial distribution of soil nutrients and mycorrhizal parameters. In a laboratory bioassay, P. pinaster and Q. ilex seedlings were grown on soils from the target sites and root colonisation by ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi was determined. The ECM root colonisation levels found indicated that soil from Site 2 contained sufficient ECM propagules to serve as a primary source of inoculum for P. pinaster. The low levels of ECM and AM colonisation obtained on the roots of plants grown in soil from Site 1 indicated that the existing mycorrhizal propagules might be insufficient for effective root colonisation of Q. ilex. Different ECM morphotypes were found in plants grown in soil from the two sites. At Site 2 mycorrhizal parameters were found to be spatially structured, with significant differences in ECM colonisation and soil P concentrations between regions of either side of an existing watercourse. The spatial distribution of mycorrhizal propagules was related to edaphic parameters (total C and extractable P), and correlations between soil nutrients and mycorrhizal parameters were found. (Author) 31 refs.

  19. Continent-wide risk assessment for the establishment of nonindigenous species in Antarctica

    Science.gov (United States)

    Chown, Steven L.; Huiskes, Ad H. L.; Gremmen, Niek J. M.; Lee, Jennifer E.; Terauds, Aleks; Crosbie, Kim; Frenot, Yves; Hughes, Kevin A.; Imura, Satoshi; Kiefer, Kate; Lebouvier, Marc; Raymond, Ben; Tsujimoto, Megumu; Ware, Chris; Van de Vijver, Bart; Bergstrom, Dana Michelle

    2012-01-01

    Invasive alien species are among the primary causes of biodiversity change globally, with the risks thereof broadly understood for most regions of the world. They are similarly thought to be among the most significant conservation threats to Antarctica, especially as climate change proceeds in the region. However, no comprehensive, continent-wide evaluation of the risks to Antarctica posed by such species has been undertaken. Here we do so by sampling, identifying, and mapping the vascular plant propagules carried by all categories of visitors to Antarctica during the International Polar Year's first season (2007–2008) and assessing propagule establishment likelihood based on their identity and origins and on spatial variation in Antarctica's climate. For an evaluation of the situation in 2100, we use modeled climates based on the Intergovernmental Panel on Climate Change's Special Report on Emissions Scenarios Scenario A1B [Nakićenović N, Swart R, eds (2000) Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change (Cambridge University Press, Cambridge, UK)]. Visitors carrying seeds average 9.5 seeds per person, although as vectors, scientists carry greater propagule loads than tourists. Annual tourist numbers (∼33,054) are higher than those of scientists (∼7,085), thus tempering these differences in propagule load. Alien species establishment is currently most likely for the Western Antarctic Peninsula. Recent founder populations of several alien species in this area corroborate these findings. With climate change, risks will grow in the Antarctic Peninsula, Ross Sea, and East Antarctic coastal regions. Our evidence-based assessment demonstrates which parts of Antarctica are at growing risk from alien species that may become invasive and provides the means to mitigate this threat now and into the future as the continent's climate changes. PMID:22393003

  20. Evaluation of mathematical methods for predicting optimum dose of gamma radiation in sugarcane (Saccharum sp.)

    International Nuclear Information System (INIS)

    Wu, K.K.; Siddiqui, S.H.; Heinz, D.J.; Ladd, S.L.

    1978-01-01

    Two mathematical methods - the reversed logarithmic method and the regression method - were used to compare the predicted and the observed optimum gamma radiation dose (OD 50 ) in vegetative propagules of sugarcane. The reversed logarithmic method, usually used in sexually propagated crops, showed the largest difference between the predicted and observed optimum dose. The regression method resulted in a better prediction of the observed values and is suggested as a better method for the prediction of optimum dose for vegetatively propagated crops. (author)

  1. The weight of the past: land-use legacies and recolonization of pine plantations by oak trees.

    Science.gov (United States)

    Navarro-González, Irene; Pérez-Luque, Antonio J; Bonet, Francisco J; Zamora, Regino

    2013-09-01

    Most of the world's plantations were established on previously disturbed sites with an intensive land-use history. Our general hypothesis was that native forest regeneration within forest plantations depends largely on in situ biological legacies as a source of propagules. To test this hypothesis, we analyzed native oak regeneration in 168 pine plantation plots in southern Spain in relation to land use in 1956, oak patch proximity, and pine tree density. Historical land-use patterns were determined from aerial photography from 1956, and these were compared with inventory data from 2004-2005 and additional orthophoto images. Our results indicate that oak forest regeneration in pine plantations depends largely on land-use legacies, although nearby, well-conserved areas can provide propagules for colonization from outside the plantation, and pine tree density also affected oak recruit density. More intense land uses in the past meant fewer biological legacies and, therefore, lower likelihood of regenerating native forest. That is, oak recruit density was lower when land use in 1956 was croplands (0.004 +/- 0.002 recruits/m2 [mean +/- SE]) or pasture (0.081 +/- 0.054 recruits/m2) instead of shrubland (0.098 +/- 0.031 recruits/m2) or oak formations (0.314 +/- 0.080 recruits/m2). Our study shows that land use in the past was more important than propagule source distance or pine tree density in explaining levels of native forest regeneration in plantations. Thus, strategies for restoring native oak forests in pine plantations may benefit from considering land-use legacies as well as distance to propagule sources and pine density.

  2. Monitoring of airborne biological particles in outdoor atmosphere. Part 2: Metagenomics applied to urban environments

    OpenAIRE

    Núñez, Andrés; Amo de Paz, Guillermo; Rastrojo, Alberto; García, Ana M.; Alcamí, Antonio; Gutiérrez-Bustillo, A. Montserrat; Moreno, Diego A.

    2016-01-01

    The air we breathe contains microscopic biological particles such as viruses, bacteria, fungi and pollen, some of them with relevant clinic importance. These organisms and/or their propagules have been traditionally studied by different disciplines and diverse methodologies like culture and microscopy. These techniques require time, expertise and also have some important biases. As a consequence, our knowledge on the total diversity and the relationships between the different biological entit...

  3. Designing marine fishery reserves using passive acoustic telemetry

    OpenAIRE

    Glazer, Robert A.; Delgado, Gabriel A.

    2006-01-01

    Marine Fishery Reserves (MFRs) are being adopted, in part, as a strategy to replenish depleted fish stocks and serve as a source for recruits to adjacent fisheries. By necessity, their design must consider the biological parameters of the species under consideration to ensure that the spawning stock is conserved while simultaneously providing propagules for dispersal. We describe how acoustic telemetry can be employed to design effective MFRs by elucidating important life-history parameters o...

  4. On a record of two alien fish species (Teleostei: Osphronemidae from the natural waters of Chennai, Tamil Nadu, India

    Directory of Open Access Journals (Sweden)

    J.D. Marcus Knight

    2015-03-01

    Full Text Available Aquarium trade has been the source of many alien species being introduced into the natural waters of Chennai.  Trichopsis vittata and Macropodus opercularis are being reported for the first from Chennai. However,  contrary to the propagule pressure theory both these species are not common in the aquarium trade, raising speculations of inter-basin water transfer playing a role in introducing non-native species into an ecosystem.  

  5. The Presence of the invasive Lionfish Pterois miles in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    M. BARICHE

    2013-06-01

    Full Text Available Here we report the occurrence of Pterois miles in the Mediterranean Sea, based on the capture of two specimens along the coast of Lebanon. Previously, only one record of the species from the Mediterranean Sea had been documented. The new records highlight the arrival of new propagules of P. miles, more than two decades later, hinting to a future potential invasion of the Mediterranean Sea.

  6. Unconventional gas development facilitates plant invasions.

    Science.gov (United States)

    Barlow, Kathryn M; Mortensen, David A; Drohan, Patrick J; Averill, Kristine M

    2017-11-01

    Vegetation removal and soil disturbance from natural resource development, combined with invasive plant propagule pressure, can increase vulnerability to plant invasions. Unconventional oil and gas development produces surface disturbance by way of well pad, road, and pipeline construction, and increased traffic. Little is known about the resulting impacts on plant community assembly, including the spread of invasive plants. Our work was conducted in Pennsylvania forests that overlay the Marcellus and Utica shale formations to determine if invasive plants have spread to edge habitat created by unconventional gas development and to investigate factors associated with their presence. A piecewise structural equation model was used to determine the direct and indirect factors associated with invasive plant establishment on well pads. The model included the following measured or calculated variables: current propagule pressure on local access roads, the spatial extent of the pre-development road network (potential source of invasive propagules), the number of wells per pad (indicator of traffic density), and pad age. Sixty-one percent of the 127 well pads surveyed had at least one invasive plant species present. Invasive plant presence on well pads was positively correlated with local propagule pressure on access roads and indirectly with road density pre-development, the number of wells, and age of the well pad. The vast reserves of unconventional oil and gas are in the early stages of development in the US. Continued development of this underground resource must be paired with careful monitoring and management of surface ecological impacts, including the spread of invasive plants. Prioritizing invasive plant monitoring in unconventional oil and gas development areas with existing roads and multi-well pads could improve early detection and control of invasive plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Monitoring Genetic Stability in Quercus serrata Thunb. Somatic Embryogenesis Using RAPD Markers

    OpenAIRE

    Ramesh C., Thakur; Susumu, Goto; Katsuaki, Ishii; S. Mohan, Jain; Forestry and Forest Products Research Institute; Fukuoka Prefecture Forest Research and Extension Center; Forestry and Forest Products Research Institute; University of Helsinki

    1999-01-01

    Genetic stability of propagules regenerated via somatic embryogenesis is of paramount importance for its application to clonal forestry. Random amplified polymorphic DNA (RAPD) markers were used to determine the genetic stability in somatic embryogenesis of Quercus serrata Thunb. (Japanese white oak). Forty samples from an embryogenic line, consisting of regenerated plantlets, somatic embryos, and embryogenic calli, were examined using 54 decanucleotide primers. A total of 6520 clear reproduc...

  8. Translocation of threatened plants as a conservation measure in China.

    Science.gov (United States)

    Liu, Hong; Ren, Hai; Liu, Qiang; Wen, XiangYing; Maunder, Michael; Gao, JiangYun

    2015-12-01

    We assessed the current status of plant conservation translocation efforts in China, a topic poorly reported in recent scientific literature. We identified 222 conservation translocation cases involving 154 species, of these 87 were Chinese endemic species and 101 (78%) were listed as threatened on the Chinese Species Red List. We categorized the life form of each species and, when possible, determined for each case the translocation type, propagule source, propagule type, and survival and reproductive parameters. A surprisingly large proportion (26%) of the conservation translocations in China were conservation introductions, largely implemented in response to large-scale habitat destruction caused by the Three-Gorge Dam and another hydropower project. Documentation and management of the translocations varied greatly. Less than half the cases had plant survival records. Statistical analyses showed that survival percentages were significantly correlated with plant life form and the type of planting materials. Thirty percent of the cases had records on whether or not individuals flowered or fruited. Results of information theoretic model selection indicated that plant life form, translocation type, propagule type, propagule source, and time since planting significantly influenced the likelihood of flowering and fruiting on the project level. We suggest that the scientific-based application of species conservation translocations should be promoted as part of a commitment to species recovery management. In addition, we recommend that the common practice of within and out of range introductions in nature reserves to be regulated more carefully due to its potential ecological risks. We recommend the establishment of a national office and database to coordinate conservation translocations in China. Our review effort is timely considering the need for a comprehensive national guideline for the newly announced nation-wide conservation program on species with extremely

  9. Evaluation of electrical conductivity of the fertiliser solution on ...

    African Journals Online (AJOL)

    The effects of three fertiliser solutions (20:20:20, 15:5:25 and 12:30:10 NPK) with electrical conductivity (EC) of 1, 1.5 or 2 mS cm-1 on growth and flowering of Cymbidium 'Sleeping Nymph' were investigated over three years. One-year-old tissue-cultured propagules of 'Sleeping Nymph' were planted singly in plastic pots in ...

  10. Introduction bias affects relationships between the characteristics of ornamental alien plants and their naturalization success

    Czech Academy of Sciences Publication Activity Database

    Maurel, N.; Hanspach, J.; Kühn, I.; Pyšek, Petr; van Kleunen, M.

    2016-01-01

    Roč. 25, č. 12 (2016), s. 1500-1509 ISSN 1466-822X R&D Projects: GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : exotic plants * propagule pressure * residence time Subject RIV: EH - Ecology, Behaviour Impact factor: 6.045, year: 2016

  11. Effects of flooding on the spatial distribution of soil seed and spore banks of native grasslands of the Pantanal wetland

    Directory of Open Access Journals (Sweden)

    Patricia Carla de Oliveira

    2015-09-01

    Full Text Available ABSTRACTTo better understand the role that flooding plays in shaping plant communities of native floodable grasslands of the Pantanal and to characterize the spatial distribution of plants, we present the results of a survey of soil seed and spore banks using the seedling emergence method. We hypothesized that terrain subjected to the deepest and longest flooding should have higher propagule abundance and richness. The species composition and distribution of seeds and spores in the soil were assessed at five sites using three sampling positions at each according to inundation intensity. In each sample position 2cm-thick soil samples were collected in quadrats to a depth of 10cm. Litter was also collected as an independent layer. Sample monitoring in the greenhouse resulted in the emergence of 5489 seedlings, or 6353 propagules.m-2. Both the litter layer and the deepest soil layer had low abundances. A total of forty-four morphospecies (16 families were recorded. Both seedling abundance and species richness were concentrated in the more floodable center sections. Isoetes pedersenii, Eleocharis minima, Sagittaria guayanensis, Rotala mexicana, Eleocharis plicarhachis, and Panicum laxum were the most abundant species. The species composition and spatial distribution of the propagule bank suggests that flooding plays a crucial role in seasonal vegetation dynamics in Pantanal wetlands, mediated by the ability of the soil to host seeds and spores during dry season.

  12. Temporal modelling of ballast water discharge and ship-mediated invasion risk to Australia.

    Science.gov (United States)

    Cope, Robert C; Prowse, Thomas A A; Ross, Joshua V; Wittmann, Talia A; Cassey, Phillip

    2015-04-01

    Biological invasions have the potential to cause extensive ecological and economic damage. Maritime trade facilitates biological invasions by transferring species in ballast water, and on ships' hulls. With volumes of maritime trade increasing globally, efforts to prevent these biological invasions are of significant importance. Both the International Maritime Organization and the Australian government have developed policy seeking to reduce the risk of these invasions. In this study, we constructed models for the transfer of ballast water into Australian waters, based on historic ballast survey data. We used these models to hindcast ballast water discharge over all vessels that arrived in Australian waters between 1999 and 2012. We used models for propagule survival to compare the risk of ballast-mediated propagule transport between ecoregions. We found that total annual ballast discharge volume into Australia more than doubled over the study period, with the vast majority of ballast water discharge and propagule pressure associated with bulk carrier traffic. As such, the ecoregions suffering the greatest risk are those associated with the export of mining commodities. As global marine trade continues to increase, effective monitoring and biosecurity policy will remain necessary to combat the risk of future marine invasion events.

  13. Air analysis in the assessment of fumonisin contamination risk in maize.

    Science.gov (United States)

    Torelli, Emanuela; Gubiani, Rino; Firrao, Giuseppe; Cividino, Sirio; Locci, Romano; Gobbi, Emanuela

    2010-03-15

    In maize-growing areas where fumonisin contamination is endemic, there is an urgent need for novel methods to assess the quality of grain lots before their delivery to common drying and storage collection centres. Aerobiological samples of fungal spores released during harvest were analysed to establish a relationship between fumonisin contamination and the abundance of pathogen propagules collected in the combine harvester using a cyclone and membrane filters. Filter-captured propagules were analysed by direct plating, immunoenzymatic assay of specific Fusarium extracellular polysaccharides and real time polymerase chain reaction of the extracted DNA using fum1, a gene involved in the biosynthesis of fumonisin, as a target. The results showed that time of harvest and environmental conditions strongly influenced the efficiency and performance of the collection system. The data obtained were informative in comparing individual samples collected under similar conditions. The immunoenzymatic assay provided the most reliable data, which improved the ability of a neural network to predict the fumonisin content of lots, when added to agronomic, environmental and phytosanitary data. This is the first attempt to evaluate the Fusarium propagules dispersed during harvesting as a predictive means to assess maize quality. A method based on cyclone/filter capture and immunological detection has been shown to be feasible and to have the potential for the development of a continuous monitoring system, but the prediction capabilities in the present implementation were limited.

  14. IN VITRO ORGANOGENESIS OF TWO SANSEVIERIA CULTIVARS ON DIFFERENT CONCENTRATIONS OF BENZYLADENINE (BA

    Directory of Open Access Journals (Sweden)

    Yusnita

    2011-06-01

    Full Text Available In vitro regeneration of buds and shoots via organogenesis in two genotypes of Sansevieria trifasciata was established. Leaf segments (1cm x 1cm of cv. Hahnii and cv. Lorentii were cultured on Murashige and Skoog (MS basal medium containing 2.4-dichloro-phenoxyacetic acid (2.4-D for 1 week, trans-ferred into MS medium without plant growth regulator (MS0 for 1 week, and then cultured to MS medium containing different concentrations of benzyladenine (BA:0; 0.1; 0.25; 0.5; 1 and 2 mg/l for 3 consecutive passages with 4 week intervals. The results showed that BA proved to be an effective cytokinin to induce the formation of adventitious buds and shoots in two cultivars of Sansevieria trifasciata. The maximum of 12 propagules per explant of Lorentii and 9.3 propagules of Hahnii were obtained in medium with 2 mg/l BA after 14 weeks. Furthermore, regenerative capacity to form shoot buds and propagules was genotype dependent. The popagules number formed by cv. Lorentii was significantly higher than those formed by cv. Hahnii. The average shoot length formed by cv. Lorentii was also higher than those of cv. Hahnii. Shoots of both cultivars were successfully ex vitro rooted and acclimatized to the greenhouse with high survival rate (95.9 -100%.

  15. Ecophysiological Response of Rhizophora mangle to the Variation in Hydrochemistry during Five Years along the Coast of Campeche, México

    Directory of Open Access Journals (Sweden)

    Carlos A. Chan-Keb

    2018-02-01

    Full Text Available We evaluated the phenological response and litterfall production of Rhizophora mangle to changes in pore water chemistry over a five-year period (from 2009 to 2014 and 2010 to 2016 along the coast of Campeche, México. Severe drought conditions were recorded in 2009 with a Standardized Precipitation Index (SPI of −1.5 and again in 2015 with a SPI of −1.16. A precipitation deficit of 22.1% was recorded between 2009 and 2016 ranging from 9.5% in Laguna de Terminos in the south to 64.4% in Los Petenes Biosphere Reserve in the north. Precipitation varied significantly per year (p < 0.001, seasonally (p < 0.001, and between years and seasons (p < 0.001. An interaction was observed in the salinity (p < 0.05, redox potential (p < 0.001, and precipitation (p < 0.001 of the Laguna de Terminos, Rio Champoton, and Los Petenes Biosphere Reserve regions. Significant differences were found between the years in the leaf and propagule production (p < 0.001, and between seasons in production of leaves, flowers, and propagules (p < 0.001. The determining factor in the production of flowers during both the rainy and dry seasons was the salinity, and the determining factors for the production of propagules were the redox potential and salinity. The results of this study suggest a low phenotypic plasticity in R. mangle.

  16. Comparison growth of Kappaphycus alvarezii (Rhodophyta, Solieriaceae cultivation in floating cage and longline in Indonesia

    Directory of Open Access Journals (Sweden)

    Ma’ruf Kasim

    2017-05-01

    Full Text Available Currently, cultivation using cages for Kappaphycus alvarezii was limited reported before. This study aims to reveal growth of K. alvarezii cultivated in floating cages and longline. The study was conducted in one of cultivation areas in Southeast Sulawesi, Indonesia. Total gross weight, propagule growth rate and specific growth rate were performing in this study. During our field experiment, total gross weight of K. alvarezii after 40 days, from 5 kg was growth to 22.5 ± 1.40 kg and 38.8 ± 1.6 kg on longline and floating cages, respectively. Propagule growth rate after 40 days, from 50 g was 107.8 ± 7.0 g and 152.5 ± 7.9 g during April, and 132.0 ± 8.0 g and 218.8 ± 8.6 g during August, on longline and floating cage, respectively. Specific growth rate of K. alvarezii was high during August, 2.43% day−1 and 3.69% day−1 cultivated in longline and floating cage, respectively. Propagule morphology was white and damage in 40% cultivated by longline and no damage by using floating cage particular in August and September while high dense of herbivorous fish surrounding the experimental sites.

  17. Dispersal of arbuscular mycorrhizal fungi and plants during succession

    Science.gov (United States)

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

    2016-11-01

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

  18. Successful biological invasion despite a severe genetic load.

    Directory of Open Access Journals (Sweden)

    Amro Zayed

    2007-09-01

    Full Text Available Understanding the factors that influence the success of ecologically and economically damaging biological invasions is of prime importance. Recent studies have shown that invasive populations typically exhibit minimal, if any, reductions in genetic diversity, suggesting that large founding populations and/or multiple introductions are required for the success of biological invasions, consistent with predictions of the propagule pressure hypothesis. Through population genetic analysis of neutral microsatellite markers and a gene experiencing balancing selection, we demonstrate that the solitary bee Lasioglossum leucozonium experienced a single and severe bottleneck during its introduction from Europe. Paradoxically, the success of L. leucozonium in its introduced range occurred despite the severe genetic load caused by single-locus complementary sex-determination that still turns 30% of female-destined eggs into sterile diploid males, thereby substantially limiting the growth potential of the introduced population. Using stochastic modeling, we show that L. leucozonium invaded North America through the introduction of a very small number of propagules, most likely a singly-mated female. Our results suggest that chance events and ecological traits of invaders are more important than propagule pressure in determining invasion success, and that the vigilance required to prevent invasions may be considerably greater than has been previously considered.

  19. Restoration potential of sedge meadows in hand-cultivated soybean fields in northeastern China

    Science.gov (United States)

    Wang, Guodong; Middleton, Beth; Jiang, Ming

    2013-01-01

    Sedge meadows can be difficult to restore from farmed fields if key structural dominants are missing from propagule banks. In hand-cultivated soybean fields in northeastern China, we asked if tussock-forming Carex and other wetland species were present as seed or asexual propagules. In the Sanjiang Plain, China, we compared the seed banks, vegetative propagules (below-ground) and standing vegetation of natural and restored sedge meadows, and hand-cultivated soybean fields in drained and flooded conditions. We found that important wetland species survived cultivation as seeds for some time (e.g. Calamogrostis angustifolia and Potamogeton crispus) and as field weeds (e.g. C. angustifolia and Phragmites australis). Key structural species were missing in these fields, for example, Carex meyeriana. We also observed that sedge meadows restored without planting or seeding lacked tussock-forming sedges. The structure of the seed bank was related to experimental water regime, and field environments of tussock height, thatch depth, and presence of burning as based on Nonmetric Multidimensional Scaling analysis. To re-establish the structure imposed by tussock sedges, specific technologies might be developed to encourage the development of tussocks in restored sedge meadows.

  20. Factors influencing the local scale colonisation and change in density of a widespread invasive plant species, Lantana camara, in South India

    Directory of Open Access Journals (Sweden)

    Bharath Sundaram

    2015-04-01

    Full Text Available Identifying factors that underlie invasive species colonisation and change in density could provide valuable insights into the mechanisms of biological invasions and for invasive species management. We examined a suite of factors potentially influencing the landscape-level invasion of Lantana camara L., one of the most ubiquitous invasive species in South Asia. These factors included disturbance factors like forest fires, historical habitat modification, and edge effects, in addition to factors like propagule pressure and habitat suitability. We examined the relative importance of these factors on the colonisation and change in density of L. camara in the Biligiri Rangaswamy Temple Tiger Reserve, Western Ghats, India. We used extensive (1997–2008 datasets tracking the presence and abundance of L. camara and combined these with corresponding data on disturbances, propagule pressure, and habitat suitability. We used an information-theoretic model selection approach to determine the relative importance of each factor on the colonisation and change in density of L. camara. Colonisation was mainly a function of proximity to already established populations (i.e. propagule pressure, whereas increase in L. camara density appeared to be constrained by high fire frequency. Research and management efforts need to recognize the multi-dimensional nature of mechanisms underlying L. camara’s success during different invasion phases when strategizing interventions to mitigate its effects.

  1. Inconsistencies among secondary sources of Chukar Partridge (Alectoris chukar introductions to the United States

    Directory of Open Access Journals (Sweden)

    Michael P. Moulton

    2015-11-01

    Full Text Available The propagule pressure hypothesis asserts that the number of individuals released is the key determinant of whether an introduction will succeed or not. It remains to be shown whether propagule pressure is more important than either species-level or site-level factors in determining the fate of an introduction. Studies claiming to show that propagule pressure is the primary determinant of introduction success must assume that the historical record as reported by secondary sources is complete and accurate. Here, examine a widely introduced game bird, the Chukar (Alectoris chukar, to the USA. We compare the records reported by two secondary sources (Long, 1981; Lever, 1987 to those in a primary source (Christensen, 1970 and to a recent study by Sol et al. (2012. Numerous inconsistencies exist in the records reported by Sol et al. (2012, Long (1981 and Lever (1987 when compared to the primary record of Christensen (1970. As reported by Christensen (1970, very large numbers of Chukars were released unsuccessfully in some states. Our results strongly imply that factors other than sheer numbers are more important. Site-to-site differences are the most likely explanation for the variation in success.

  2. Synthesis, characterization and antimicrobial evaluation of some arylidenehydrazonofuropyrimidines and thienopyrimidines

    International Nuclear Information System (INIS)

    Bhuiyan, M.M.H.; Rahman, M.M.; Islam, M.I.

    2009-01-01

    Cyclization of heteroaromatic o-aminoester with formamide afforded furo(2,3-d)pyrimidin-4(3H)-one which was then chlorinated with thionyl chloride followed by displacement by hydrazine hydrate to furnish hydrazinofuro (2,3-d)pyrimidine. Reaction of hydrazino derivative with formic acid gave furo(3,2-e)(1,2,4)triazolo(4,3-c)pyrimidine. Treatment of hydrazino derivative with aromatic aldehydes afforded arylidenehydrazonofuro(2,3-d)pyrimidine derivatives. Reaction of o-aminonitrile with carbon disulphide, followed by methylation with methyl iodide and subsequent reaction with hydrazine hydrate afforded hydrazinothieno (2,3-d)pyrimidine. 14 derivatives were synthesized. Some of these derivatives exhibited pronounced antimicrobial activities against S. typhi, S. aureus, S. dysenteriae, V. cholerae, C. lunata, A. alternata, C. corchori, F. equeseti and M. phaseolina. (author)

  3. Root rot diseases of sugar beet

    Directory of Open Access Journals (Sweden)

    Jacobsen Barry J.

    2006-01-01

    Full Text Available Root rot diseases of sugar beet caused by Rhizoctonia solani (AG 2-2 IIIB and AG 2-2 IV, R. crocorum, Aphanomyces cochlioides, Phoma betae, Macrophomina phaeseolina, Fusarium oxysporum f.sp. radicis-betae, Pythium aphanidermatum Phytophthora drechsleri, Rhizopus stolonifer, R. arrhizus and Sclerotium rolfsii cause significant losses wherever sugar beets are grown. However, not all these soil-borne pathogens have been reported in all sugar beet production areas. Losses include reduced harvestable tonnage and reduced white sugar recovery. Many of these pathogens also cause post harvest losses in storage piles. Control for diseases caused by these pathogens include disease resistant cultivars, avoidance of stresses, cultural practices such as water management and the use of fungicides.

  4. High yielding and disease resistant mutants of sorghum in Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Reinoso, A; Murty, B R; Taborda, F [Faculty of Agronomy, University of Zulia, Maracaibo (Venezuela)

    1987-07-01

    The programme was assisted by IAEA under project VEN/5/005 since 1978. It aims at improvement of plant type, earliness and resistance to Macrophomina in the locally adapted varieties Criollo Rojo Pequeno (CRP) and Criollo Blanco Alto (CBA). The mutagenic treatment consisted of seed irradiation at 20, 30 and 40 kR of gamma rays and chemical mutagenesis using sodium azide followed by 5000 kR gamma radiation. The 16 best mutants were evaluated in multilocation trials during M{sub 6}-M{sub 9} 1981-1984: Mutants from CRP namely 1279, 1543, 1265, 2085, 1251 and 1359 and four mutant from CBA, 109, 467, 469 and 81-1227 were found to be superior to their parents and the existing commercial hybrids. CRP 1279, 1543 and 2085 are already under large scale cultivation by farmers and under process for cultivar certification by the Ministry of Agriculture.

  5. A New Biocontrol Fungus Trichoderma Kongii in the Kingdom of Saudi Arabia Isolation and Identification

    International Nuclear Information System (INIS)

    AlYahya, F.A; ElHussieni, S.M; Ibrahim, A.A; Ibrahim, Y.E

    2007-01-01

    A total of 164 soil and root samples of different plant groups were collected from Abu-Arish governorate , Jazan province South West Saudi Arabia during the period of 2004-2005. Each sample contained feeder roots and approximately 250 g soil, taken from a depth of 20 cm of the soil surface. Samples were analyzed by two different media. Culture fungi on Malt Extract Agar identified by Biolog Systems and culture fungi on Potato Dextrose Agar medium containing chloramphenicol were identified by microscopic characterization. Results showed that, 11 different types of fungi isolated from tested samples, Fusarium spp (40%), Rhizoctonia solani,(12%) Trichoderma spp (12%), Macrophomina phaseoina. (7 %), Aspergillus spp (18 %) were the predominant fungal species. Helminthosporium spp (3%), Alternaria alternate (2%), Pythium spp (2%), Curviularia spp (2%), Cladsporium spp. (1%) and Mucor spp. (1%) were less frequent. (author)

  6. High yielding and disease resistant mutants of sorghum in Venezuela

    International Nuclear Information System (INIS)

    Reinoso, A.; Murty, B.R.; Taborda, F.

    1987-01-01

    The programme was assisted by IAEA under project VEN/5/005 since 1978. It aims at improvement of plant type, earliness and resistance to Macrophomina in the locally adapted varieties Criollo Rojo Pequeno (CRP) and Criollo Blanco Alto (CBA). The mutagenic treatment consisted of seed irradiation at 20, 30 and 40 kR of gamma rays and chemical mutagenesis using sodium azide followed by 5000 kR gamma radiation. The 16 best mutants were evaluated in multilocation trials during M 6 -M 9 1981-1984: Mutants from CRP namely 1279, 1543, 1265, 2085, 1251 and 1359 and four mutant from CBA, 109, 467, 469 and 81-1227 were found to be superior to their parents and the existing commercial hybrids. CRP 1279, 1543 and 2085 are already under large scale cultivation by farmers and under process for cultivar certification by the Ministry of Agriculture

  7. ANTIFUNGAL AND CYTOTOXIC ACTIVITIES OF FIVE TRADITIONALLY USED INDIAN MEDICINAL PLANTS

    Directory of Open Access Journals (Sweden)

    Adhikarimayum Haripyaree

    2013-02-01

    Full Text Available Hexane, Methanol and Distilled water extracts of five Indian Medicinal plants viz., Mimosa pudica L, Vitex trifolia Linn, Leucas aspera Spreng, Centella asiatica (L Urban and Plantago major Linn belonging to different families were subjected to preliminary antimicrobial screening against six standard organisms viz., Ceratocystis paradoxa, Aspergillus niger, Penicillium citrinum, Macrophomina phaseoli, Trichoderma viride and Rhizopus nigricans. To evaluate antifungal activity agar well diffusion method was used. In addition LD50 of the same plant extracts were determined by using Range test on Mus musculus for cytotoxic activity. Methanolic extract of M. pudica showed the highest and significant inhibitory effect against some fungal species. Again, methanolic extract of M. pudica displayed the greatest cytotoxic activity.

  8. Mutation breeding in Ajonjoli (Sesamum indicum, L.) for adaptation to the cropping system in Venezuela

    International Nuclear Information System (INIS)

    Oropeza, F.; Murty, B.R.; Bravo, R.M.

    1984-01-01

    Sesame, the main edible oil crop in Venezuela, is grown in a cropping system under peculiar ecological conditions after rice, sorghum or maize on residual moisture. The yields are variable with 350 to 500 Kg/Ha. The available varieties are not synchronous in flowering, have poor root development, and are susceptible to Fusarium sp, Phytophtora and Macrophomina. Some are very late (more than 115 days) with 1-3 capsules of variable size and unpredictable yield. A mutational rectification program using locally adapted varieties was started in 1981, to develop material suitable for the above ecological conditions. The main characteristics for improvement are: earliness, with maturity of 75 to 90 days, synchronous flowering, uniform ripening, indehiscence at harvesting but easy threshing, suitable plant type for mechanical harvesting, resistance specially to Macrophomina spp, without adverse effect on oil content, quality and yield and improved productivity and stability under moisture stress and improved fertilizer utilization. Eight varieties were treated with gamma radiation from Csub(o) 60 at 0, 20, 40, 60, 80 KR to determine varietal responses. The results show marked varietal differences in germination, growth and survival. The other three varieties: Aceitera, Arawaca, Turen were the most susceptible to radiation, while Glauca was the most resistant. Probit analysis of data for germination, vigor seedling height and survival revealed that no single character is adequate to determine LD 50 dose in mutation breeding. The need for taking all the parameters of regression analysis like b-tilde, and σ-circumflex to characterize varietal responses is discussed along with plans for the next stage of work. (author)

  9. Effects of nematicides on cotton root mycobiota.

    Science.gov (United States)

    Baird, R E; Carling, D E; Watson, C E; Scruggs, M L; Hightower, P

    2004-02-01

    Baseline information on the diversity and population densities of fungi collected from soil debris and cotton (Gossypium hirsutum L.) roots was determined. Samples were collected from Tifton, GA, and Starkville, MS containing cotton field soil treated with the nematicides 1,3-dichloroproprene (fumigant) and aldicarb (granules). A total of 10,550 and 13,450 fungal isolates were collected from these two study sites, respectively. Of this total, 34 genera of plant pathogenic or saprophytic species were identified. Pathogenic root fungi included Fusarium spp. (40% of all isolations), Macrophomina, Pythium, Rhizoctonia, and Sclerotium. Fusarium and Rhizoctonia were the most common fungal species identified and included F. oxysporum, F. verticillioides and F. solani, the three Fusarium species pathogenic on cotton plants. Population densities of Fusarium were not significantly different among locations or tissue types sampled. Macrophomina was isolated at greater numbers near the end of the growing seasons. Anastomosis groups of R. solani isolated from roots and soil debris included AG-3, -4, -7, 2-2, and -13 and anastomosis groups of binucleate Rhizoctonia included CAG-2, -3, and -5. Occurrences and frequency of isolations among sampling dates were not consistent. Fluctuations in the frequency of isolation of Rhizoctonia did not correspond with changes in frequency of isolation of the biological control fungus, Trichoderma. When individual or pooled frequencies of the mycobiota were compared to nematicide treatments, no specific trends occurred between treatments, application methods or rates. Results from this study show that use of 1,3-D and aldicarb in cotton fields does not significantly impact plant pathogenic fungi or saprophytic fungal populations. Thus cotton producers need not adjust seedling disease control measures when these two nematicides are used.

  10. Landscape management and domestication of Stenocereus pruinosus (Cactaceae) in the Tehuacán Valley: human guided selection and gene flow

    Science.gov (United States)

    2012-01-01

    Background Use of plant resources and ecosystems practiced by indigenous peoples of Mesoamerica commonly involves domestication of plant populations and landscapes. Our study analyzed interactions of coexisting wild and managed populations of the pitaya Stenocereus pruinosus, a columnar cactus used for its edible fruit occurring in natural forests, silviculturally managed in milpa agroforestry systems, and agriculturally managed in homegardens of the Tehuacán Valley, Mexico. We aimed at analyzing criteria of artificial selection and their consequences on phenotypic diversity and differentiation, as well as documenting management of propagules at landscape level and their possible contribution to gene flow among populations. Methods Semi-structured interviews were conducted to 83 households of the region to document perception of variation, criteria of artificial selection, and patterns of moving propagules among wild and managed populations. Morphological variation of trees from nine wild, silviculturally and agriculturally managed populations was analyzed for 37 characters through univariate and multivariate statistical methods. In addition, indexes of morphological diversity (MD) per population and phenotypic differentiation (PD) among populations were calculated using character states and frequencies. Results People recognized 15 pitaya varieties based on their pulp color, fruit size, form, flavor, and thorniness. On average, in wild populations we recorded one variety per population, in silviculturally managed populations 1.58 ± 0.77 varieties per parcel, and in agriculturally managed populations 2.19 ± 1.12 varieties per homegarden. Farmers select in favor of sweet flavor (71% of households interviewed) and pulp color (46%) mainly red, orange and yellow. Artificial selection is practiced in homegardens and 65% of people interviewed also do it in agroforestry systems. People obtain fruit and branches from different population types and move

  11. Growth and population dynamics during early stages of the mangrove Kandelia candel in Halong Bay, North Viet Nam

    Science.gov (United States)

    Thi Ha, Hoang; Duarte, Carlos M.; Tri, Nguyen Hoang; Terrados, Jorge; Borum, Jens

    2003-11-01

    Quantifying the dynamics of the early stages in the life cycle of mangroves is essential to predict the distribution, species composition and structure of mangrove forests, and their maintenance and recovery from perturbations. The growth and population dynamics of two stands of the mangrove Kandelia candel in Halong Bay (Viet Nam) were examined for 1 year. Growth was highly seasonal, with high growth rates and fast internode formation in the summer, dropping to extremely low growth during January-February, the coldest and driest months in the year. In addition, growth and internode formation rates showed important inter-annual variability during the last decade. The complete reproductive period required 7-8 months. Flower initiation was maximal in June and peak propagule maturity occurred in December-January. Only one mature propagule developed for every 67 and 127 inflorescence buds formed at Site 1 and Site 2, respectively. Kandelia candel propagules begun to sink 10 days after being released, and after 18 days all propagules had negative buoyancy. The propagules developed roots within 19-68 days, depending on whether they were held on the water or sediment, and were capable of long range dispersal, for 15-20% of them dispersed more than 100 m within 1 day. The median age of K. candel plants ranged between 8.7 and 5.6 years, with a density of 1900 and 470 plants ha -1, in Sites 1 and 2. Plant mortality was high, with 64 and 74% of the plants surviving after a year at Sites 1 and 2. Life expectancy (i.e. median age-at-death) of only 2.2 and 2.7 years at Sites 1 and 2, respectively, indicates that mortality of young K. candel plants was specially high. Recruitment occurred in early spring, and did not suffice to balance the mortality within the annual period examined. These results suggest that the K. candel stands in Halong Bay might be maintained by a few years of high recruitment which would compensate for generally high mortality rates.

  12. Landscape management and domestication of Stenocereus pruinosus (Cactaceae) in the Tehuacán Valley: human guided selection and gene flow.

    Science.gov (United States)

    Parra, Fabiola; Blancas, José Juan; Casas, Alejandro

    2012-08-14

    Use of plant resources and ecosystems practiced by indigenous peoples of Mesoamerica commonly involves domestication of plant populations and landscapes. Our study analyzed interactions of coexisting wild and managed populations of the pitaya Stenocereus pruinosus, a columnar cactus used for its edible fruit occurring in natural forests, silviculturally managed in milpa agroforestry systems, and agriculturally managed in homegardens of the Tehuacán Valley, Mexico. We aimed at analyzing criteria of artificial selection and their consequences on phenotypic diversity and differentiation, as well as documenting management of propagules at landscape level and their possible contribution to gene flow among populations. Semi-structured interviews were conducted to 83 households of the region to document perception of variation, criteria of artificial selection, and patterns of moving propagules among wild and managed populations. Morphological variation of trees from nine wild, silviculturally and agriculturally managed populations was analyzed for 37 characters through univariate and multivariate statistical methods. In addition, indexes of morphological diversity (MD) per population and phenotypic differentiation (PD) among populations were calculated using character states and frequencies. People recognized 15 pitaya varieties based on their pulp color, fruit size, form, flavor, and thorniness. On average, in wild populations we recorded one variety per population, in silviculturally managed populations 1.58 ± 0.77 varieties per parcel, and in agriculturally managed populations 2.19 ± 1.12 varieties per homegarden. Farmers select in favor of sweet flavor (71% of households interviewed) and pulp color (46%) mainly red, orange and yellow. Artificial selection is practiced in homegardens and 65% of people interviewed also do it in agroforestry systems. People obtain fruit and branches from different population types and move propagules from one another. Multivariate

  13. Plants promote mating and dispersal of the human pathogenic fungus Cryptococcus.

    Directory of Open Access Journals (Sweden)

    Deborah J Springer

    Full Text Available Infections due to Cryptococcus are a leading cause of fungal infections worldwide and are acquired as a result of environmental exposure to desiccated yeast or spores. The ability of Cryptococcus to grow, mate, and produce infectious propagules in association with plants is important for the maintenance of the genetic diversity and virulence factors important for infection of animals and humans. In the Western United States and Canada, Cryptococcus has been associated with conifers and tree species other than Eucalyptus; however, to date Cryptococcus has only been studied on live Arabidopsis thaliana, Eucalyptus sp., and Terminalia catappa (almond seedlings. Previous research has demonstrated the ability of Cryptococcus to colonize live plants, leaves, and vasculature. We investigated the ability of Cryptococcus to grow on live seedlings of the angiosperms, A. thaliana, Eucalyptus camaldulensis, Colophospermum mopane, and the gymnosperms, Pseudotsuga menziesii (Douglas fir, and Tsuga heterophylla (Western hemlock. We observed a broad-range ability of Cryptococcus to colonize both traditional infection models as well as newly tested conifer species. Furthermore, C. neoformans, C. deneoformans, C. gattii (VGI, C. deuterogattii (VGII and C. bacillisporus (VGIII were able to colonize live plant leaves and needles but also undergo filamentation and mating on agar seeded with plant materials or in saprobic association with dead plant materials. The ability of Cryptococcus to grow and undergo filamentation and reproduction in saprobic association with both angiosperms and gymnosperms highlights an important role of plant debris in the sexual cycle and exposure to infectious propagules. This study highlights the broad importance of plants (and plant debris as the ecological niche and reservoirs of infectious propagules of Cryptococcus in the environment.

  14. Pemanfaatan Bahan Organik sebagai Pembawa untuk Peningkatan Kepadatan Populasi Trichoderma viride pada Rizosfir pisang dan Pengaruhnya terhadap Penyakit Layu Fusarium

    Directory of Open Access Journals (Sweden)

    . Nurbailis

    2011-11-01

    Full Text Available The aims of the research were to determine the best organic matter as carrier for growth and increasing the density of Trichoderma viride strain TV-T1sk (TV-T1sk and its influence on Fusarium wilt disease development on banana seedling.  This research consisted of two experiments, i.e. (1. Growth  testing of TV-T1sk  in various organic matter, (2. Various organic matter testing for increasing the density of TV-T1sk in banana rhizosphere and its influence on  Fusarium wilt desease development.  The treatments were various organic matter, namely rice straw, sugar cane pulp, rice bran+banana plant waste,  hull of rice+sugar cane pulp and rice. The variables observed were  density and viability of conidia on various organic matter. Propagule density after introduction to banana rhizosphere was determined by observing TV-T1sk propagul from the rizosphere of banana seedling. The influence of density on Fusarium wilt disease development was determined by incubation period, the percentage of symptomized leaves and the intensity of corm damage. The results showed that both sugar cane pulp and rice were the best organic matter  for increasing  the growth and the density  of TV-T1sk  after introduction to banana rhizosphere. The density of TV-T1sk propagule on banana rhizophere influenced  the development of Fusarium wilt disease.

  15. Modeling invasive alien plant species in river systems: Interaction with native ecosystem engineers and effects on hydro-morphodynamic processes

    Science.gov (United States)

    van Oorschot, M.; Kleinhans, M. G.; Geerling, G. W.; Egger, G.; Leuven, R. S. E. W.; Middelkoop, H.

    2017-08-01

    Invasive alien plant species negatively impact native plant communities by out-competing species or changing abiotic and biotic conditions in their introduced range. River systems are especially vulnerable to biological invasions, because waterways can function as invasion corridors. Understanding interactions of invasive and native species and their combined effects on river dynamics is essential for developing cost-effective management strategies. However, numerical models for simulating long-term effects of these processes are lacking. This paper investigates how an invasive alien plant species affects native riparian vegetation and hydro-morphodynamics. A morphodynamic model has been coupled to a dynamic vegetation model that predicts establishment, growth and mortality of riparian trees. We introduced an invasive alien species with life-history traits based on Japanese Knotweed (Fallopia japonica), and investigated effects of low- and high propagule pressure on invasion speed, native vegetation and hydro-morphodynamic processes. Results show that high propagule pressure leads to a decline in native species cover due to competition and the creation of unfavorable native colonization sites. With low propagule pressure the invader facilitates native seedling survival by creating favorable hydro-morphodynamic conditions at colonization sites. With high invader abundance, water levels are raised and sediment transport is reduced during the growing season. In winter, when the above-ground invader biomass is gone, results are reversed and the floodplain is more prone to erosion. Invasion effects thus depend on seasonal above- and below ground dynamic vegetation properties and persistence of the invader, on the characteristics of native species it replaces, and the combined interactions with hydro-morphodynamics.

  16. Artificial coastal lagoons at solar salt-working sites: A network of habitats for specialised, protected and alien biodiversity

    Science.gov (United States)

    Herbert, Roger J. H.; Broderick, Lee G.; Ross, Kathryn; Moody, Chris; Cruz, Tamira; Clarke, Leo; Stillman, Richard A.

    2018-04-01

    There are concerns that novel structures might displace protected species, facilitate the spread of non-indigenous species, or modify native habitats. It is also predicted that ocean warming and the associated effects of climate change will significantly increase biodiversity loss within coastal regions. Resilience is to a large extent influenced by the magnitude of dispersal and level of connectivity within and between populations. Therefore it is important to investigate the distribution and ecological significance of novel and artificial habitats, the presence of protected and alien species and potential vectors of propagule dispersal. The legacy of solar salt-making in tropical and warm temperate regions is regionally extensive areas of artificial hypersaline ponds, canals and ditches. Yet the broad-scale contribution of salt-working to a network of benthic biodiversity has not been fully established. Artisanal, abandoned and historic salt-working sites were investigated along the Atlantic coast of Europe between southern England (50°N) and Andalucía, Spain (36°N). Natural lagoons are scarce along this macrotidal coast and are vulnerable to environmental change; however it is suspected that avian propagule dispersal is important in maintaining population connectivity. During bird migration periods, benthic cores were collected for infauna from 70 waterbodies across 21 salt-working sites in 5 coastal regions. Bird ringing data were used to investigate potential avian connectivity between locations. Lagoonal specialist species, some of international conservation importance, were recorded across all regions in the storage reservoirs and evaporation ponds of continental salinas, yet few non-indigenous species were observed. Potential avian propagule transport and connectivity within and between extant salt-working sites is high and these artificial habitats are likely to contribute significantly to a network of coastal lagoon biodiversity in Europe.

  17. Connectivity diagnostics in the Mediterranean obtained from Lagrangian Flow Networks; global patterns, sensitivity and robustness

    Science.gov (United States)

    Monroy, Pedro; Rossi, Vincent; Ser-Giacomi, Enrico; López, Cristóbal; Hernández-García, Emilio

    2017-04-01

    Lagrangian Flow Network (LFN) is a modeling framework in which geographical sub-areas of the ocean are represented as nodes in a network and are interconnected by links representing the transport of water, substances or propagules (eggs and larvae) by currents. Here we compute for the surface of the whole Mediterranean basin four connectivity metrics derived from LFN that measure retention and exchange processes, thus providing a systematic characterization of propagule dispersal driven by the ocean circulation. Then we assess the sensitivity and robustness of the results with respect to the most relevant parameters: the density of released particles, the node size (spatial-scales of discretization), the Pelagic Larval Duration (PLD) and the modality of spawning. We find a threshold for the number of particles per node that guarantees reliable values for most of the metrics examined, independently of node size. For our setup, this threshold is 100 particles per node. We also find that the size of network nodes has a non-trivial influence on the spatial variability of both exchange and retention metrics. Although the spatio-temporal fluctuations of the circulation affect larval transport in a complex and unpredictable manner, our analyses evidence how specific biological parametrization impact the robustness of connectivity diagnostics. Connectivity estimates for long PLDs are more robust against biological uncertainties (PLD and spawning date) than for short PLDs. Furthermore, our model suggests that for mass-spawners that release propagules over short periods (≃ 2 to 10 days), daily release must be simulated to properly consider connectivity fluctuations. In contrast, average connectivity estimates for species that spawn repeatedly over longer duration (a few weeks to a few months) remain robust even using longer periodicity (5 to 10 days). Our results give a global view of the surface connectivity of the Mediterranean Sea and have implications for the design of

  18. Diversity of arbuscular mycorrhizal fungi in a chrono-sequence of alluvial and degraded soils due to mining processes in bajo cauca antioqueno, Colombia

    International Nuclear Information System (INIS)

    Medina S, Marisol; Orozco P, Francisco H; Marquez F, Maria E

    2009-01-01

    Arbuscular mycorrhizal fungi (AMF) presence and diversity were evaluated in undisturbed and disturbed soils form alluvial mining processes. The soils belong to the Tropic Fluvaquent, Typical Dystropept, and Typical Paleudult sub-groups which corresponded to Low, Middle and High terraces, respectively, of the Cauca river at Taraza town. AMF propagules were multiplied in Leonard jars under glass house conditions using sterile substrate, modified Hoagland's solution and different fractions of soil used as sources of inoculum, which corresponded to the size of the spores. A first assay was made in maize (Zea mays) which allowed mycorrhizal colonization in roots but not spore production. In a second assay, in kudzu (Pueraria phaseoloides) AMF spores and colonized roots were obtained with the treatments corresponding to propagules obtained from high terrace and disturbed soil. These treatments presented a significant effect on kudzu yield (P?0,001) respect to the other treatments. The AMF spores of undisturbed and disturbed soils showed low infective capacity. Nevertheless, propagules of AMF were multiplied in trap cultures, which produced spores of four morpho types. One of these was identified as G. microagregatum. The polymorphism obtained by RAPD's made possible the differentiation of these morpho types with the primer OPA2. Similitude above 38% was achieved using UPGMA system. The results indicated that four morpho types belong to the genus Glomus, but they possibly belong to different species. Our results are promissory in the differentiation of native strains of AMF with low number of spores collected from soil samples in rehabilitation processes, which normally is unknown.

  19. Diversity of arbuscular mycorrhizal fungi in a chrono-sequence of alluvial and degraded soils due to mining processes in bajo cauca antioqueno, Colombia; Diversidad de hongos micorrizogenos arbusculares de una crono-secuencia de suelos aluviales degradados por actividad minera en el bajo Cauca antioqueno, Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Medina S, Marisol; Orozco P, Francisco H; Marquez F, Maria E

    2009-07-01

    Arbuscular mycorrhizal fungi (AMF) presence and diversity were evaluated in undisturbed and disturbed soils form alluvial mining processes. The soils belong to the Tropic Fluvaquent, Typical Dystropept, and Typical Paleudult sub-groups which corresponded to Low, Middle and High terraces, respectively, of the Cauca river at Taraza town. AMF propagules were multiplied in Leonard jars under glass house conditions using sterile substrate, modified Hoagland's solution and different fractions of soil used as sources of inoculum, which corresponded to the size of the spores. A first assay was made in maize (Zea mays) which allowed mycorrhizal colonization in roots but not spore production. In a second assay, in kudzu (Pueraria phaseoloides) AMF spores and colonized roots were obtained with the treatments corresponding to propagules obtained from high terrace and disturbed soil. These treatments presented a significant effect on kudzu yield (P?0,001) respect to the other treatments. The AMF spores of undisturbed and disturbed soils showed low infective capacity. Nevertheless, propagules of AMF were multiplied in trap cultures, which produced spores of four morpho types. One of these was identified as G. microagregatum. The polymorphism obtained by RAPD's made possible the differentiation of these morpho types with the primer OPA2. Similitude above 38% was achieved using UPGMA system. The results indicated that four morpho types belong to the genus Glomus, but they possibly belong to different species. Our results are promissory in the differentiation of native strains of AMF with low number of spores collected from soil samples in rehabilitation processes, which normally is unknown.

  20. Ectoparasites may serve as vectors for the white-nose syndrome fungus.

    Science.gov (United States)

    Lučan, Radek K; Bandouchova, Hana; Bartonička, Tomáš; Pikula, Jiri; Zahradníková, Alexandra; Zukal, Jan; Martínková, Natália

    2016-01-13

    Vertebrate ectoparasites frequently play a role in transmission of infectious agents. Pseudogymnoascus destructans is a psychrophilic fungus known to cause white-nose syndrome (WNS), an emerging infectious disease of bats. It is transmitted with direct contact between bats or with contaminated environment. The aim of this study was to examine wing mites from the family Spinturnicidae parasitizing hibernating bats for the presence of P. destructans propagules as another possible transmission route. Wing mites collected from 33 bats at four hibernation sites in the Czech Republic were inspected for the presence and load of pathogen's DNA using quantitative PCR. Simultaneously, wing damage of inspected bats caused by WNS was quantified using ultraviolet light (UV) transillumination and the relationship between fungal load on wing mites and intensity of infection was subjected to correlation analysis. All samples of wing mites were positive for the presence of DNA of P. destructans, indicating a high probability of their role in the transmission of the pathogen's propagules between bats. Mechanical transport of adhesive P. destructans spores and mycelium fragments on the body of spinturnicid mites is highly feasible. The specialised lifestyle of mites, i.e., living on bat wing membranes, the sites most typically affected by fungal growth, enables pathogen transport. Moreover, P. destructans metabolic traits suggest an ability to grow and sporulate on a range of organic substrates, including insects, which supports the possibility of growth on bat ectoparasites, at least in periods when bats roost in cold environments and enter torpor. In addition to transport of fungal propagules, mites may facilitate entry of fungal hyphae into the epidermis through injuries caused by biting.

  1. Biological legacies: Direct early ecosystem recovery and food web reorganization after a volcanic eruption in Alaska

    Science.gov (United States)

    Walker, Lawrence R.; Sikes, Derek S.; DeGange, Anthony R.; Jewett, Stephen C.; Michaelson, Gary; Talbot, Sandra L.; Talbot, Stephen S.; Wang, Bronwen; Williams, Jeffrey C.

    2014-01-01

    Attempts to understand how communities assemble following a disturbance are challenged by the difficulty of determining the relative importance of stochastic and deterministic processes. Biological legacies, which result from organisms that survive a disturbance, can favour deterministic processes in community assembly and improve predictions of successional trajectories. Recently disturbed ecosystems are often so rapidly colonized by propagules that the role of biological legacies is obscured. We studied biological legacies on a remote volcanic island in Alaska following a devastating eruption where the role of colonization from adjacent communities was minimized. The role of biological legacies in the near shore environment was not clear, because although some kelp survived, they were presumably overwhelmed by the many vagile propagules in a marine environment. The legacy concept was most applicable to terrestrial invertebrates and plants that survived in remnants of buried soil that were exposed by post-eruption erosion. If the legacy concept is extended to include ex situ survival by transient organisms, then it was also applicable to the island's thousands of seabirds, because the seabirds survived the eruption by leaving the island and have begun to return and rebuild their nests as local conditions improve. Our multi-trophic examination of biological legacies in a successional context suggests that the relative importance of biological legacies varies with the degree of destruction, the availability of colonizing propagules, the spatial and temporal scales under consideration, and species interactions. Understanding the role of biological legacies in community assembly following disturbances can help elucidate the relative importance of colonists versus survivors, the role of priority effects among the colonists, convergence versus divergence of successional trajectories, the influence of spatial heterogeneity, and the role of island biogeographical concepts.

  2. Comparison of fungal spores concentrations measured with wideband integrated bioaerosol sensor and Hirst methodology

    Science.gov (United States)

    Fernández-Rodríguez, S.; Tormo-Molina, R.; Lemonis, N.; Clot, B.; O'Connor, D. J.; Sodeau, John R.

    2018-02-01

    The aim of this work was to provide both a comparison of traditional and novel methodologies for airborne spores detection (i.e. the Hirst Burkard trap and WIBS-4) and the first quantitative study of airborne fungal concentrations in Payerne (Western Switzerland) as well as their relation to meteorological parameters. From the traditional method -Hirst trap and microscope analysis-, sixty-three propagule types (spores, sporangia and hyphae) were identified and the average spore concentrations measured over the full period amounted to 4145 ± 263.0 spores/m3. Maximum values were reached on July 19th and on August 6th. Twenty-six spore types reached average levels above 10 spores/m3. Airborne fungal propagules in Payerne showed a clear seasonal pattern, increasing from low values in early spring to maxima in summer. Daily average concentrations above 5000 spores/m3 were almost constant in summer from mid-June onwards. Weather parameters showed a relevant role for determining the observed spore concentrations. Coniferous forest, dominant in the surroundings, may be a relevant source for airborne fungal propagules as their distribution and predominant wind directions are consistent with the origin. The comparison between the two methodologies used in this campaign showed remarkably consistent patterns throughout the campaign. A correlation coefficient of 0.9 (CI 0.76-0.96) was seen between the two over the time period for daily resolutions (Hirst trap and WIBS-4). This apparent co-linearity was seen to fall away once increased resolution was employed. However at higher resolutions upon removal of Cladosporium species from the total fungal concentrations (Hirst trap), an increased correlation coefficient was again noted between the two instruments (R = 0.81 with confidence intervals of 0.74 and 0.86).

  3. Inoculum density of Glomus mosseae and growth of onion plants in unsterilized bituminous coal spoil

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A.G.

    1988-01-01

    The effect of inoculum, density (number of vesicular-arbuscular mycorrhizal (VAM) propagules g/sup -1/ of inoculum) on the growth of onions (Allium cepa L.) infected by Glomus mosseae (Nicol and Gerd). Gerdemann and Trappe, Comb nov in unsterilized coal spoil containing indigenous VAM fungi, including G. mosseae, was investigated. The amount of onion roots converted to mycorrhizas by inoculant fungus, estimated by a gridline intersect method, increased with inoculum density (..gamma..0.62, P0.05) until a plateau was reached. Onion growth responses also increased significantly (P<0.05) with the amount of VAM inoculum present in the coal spoil. The initial linear relationship between inoculum propagules (MPN estimates), percent colonization of onion roots and onion shoot dry weight became quadratic as the number of infection propagules increased. VAM infection had no significant effect on root:shoot ratios. Similarly there was no significant interaction (P>0.05) between the inoculum density, VAM-colonized root mass and the onion root:shoot fresh weight ratios. The amount of the windswept bituminous coal spoil bound to VAM (presumably because of VAM external hyphae) also increased as inoculum density increased (..gamma..0.63, P<0.05). There was a stronger correlation (ga0.85, P<0.05) between the amount of spoil adhered per plant and the root fresh wt plant/sup -1/ indicating that root effects were primarily responsible for increasing spoil adherence. There were negative correlations (P<0.05) between root fresh wt plant/sup -1/ (..gamma..-0.68), inoculum density (..gamma..-0.589), percent root elngth infected (..gamma..-0.73) and the amount of spoil adhered g/sup -1/ root fresh wt. The possible exploitation of VAM in revegetation of bituminous coal spoil is discussed. 25 refs., 2 tabs.

  4. Adaptive introductions: How multiple experiments and comparisons to wild populations provide insights into requirements for long-term introduction success of an endangered shrub

    Directory of Open Access Journals (Sweden)

    Eric S. Menges

    2016-10-01

    Full Text Available Recovery of an imperiled plant species may require augmentation of existing populations or creation of new ones. Hundreds of such projects have been conducted over the last few decades, but there is a bias in the literature favoring successes over failures. In this paper, we evaluate a series of introductions that experimentally manipulated microhabitat and fire in an adaptive introduction framework. Between 2002 and 2012, we (and our collaborators carried out ten introductions and augmentations of Florida ziziphus Pseudoziziphus (Condalia, Ziziphus celata, a clonal shrub limited to very small populations and narrowly endemic to pyrogenic central Florida sandhills. Six of the introductions were designed as experiments to test hypotheses about how demographic performance was affected by microhabitat, fire, and propagule type. Introduced transplants had high survival (<90% annually, inconsistent growth, and little transition to reproduction, while introduced seeds had low germination and survival. Transplants were more efficient than seeds as translocation propagules. Shaded (vs. open sites supported generally higher transplant and seedling survival and seed germination percentages, but growth responses varied among experiments. Supplemental irrigation increased transplant survival and seed germination, but otherwise seedling and plant survival and growth were not significantly affected. Contrary to expectations based on wild populations, introduced propagules have not been more successful in unshaded sites, suggesting that Florida ziziphus has broader microhabitat preferences than hypothesized. Compared to wild plants, introduced plants had similar survival and responses to fire, slower growth, and more delayed flowering. Introduced plants had no clonal spread. While no introduced population has demonstrated a capacity for long-term viability, one augmented population has flowered and produced viable fruits. Given that Florida ziziphus genets are

  5. Visibility from roads predict the distribution of invasive fishes in agricultural ponds.

    Science.gov (United States)

    Kizuka, Toshikazu; Akasaka, Munemitsu; Kadoya, Taku; Takamura, Noriko

    2014-01-01

    Propagule pressure and habitat characteristics are important factors used to predict the distribution of invasive alien species. For species exhibiting strong propagule pressure because of human-mediated introduction of species, indicators of introduction potential must represent the behavioral characteristics of humans. This study examined 64 agricultural ponds to assess the visibility of ponds from surrounding roads and its value as a surrogate of propagule pressure to explain the presence and absence of two invasive fish species. A three-dimensional viewshed analysis using a geographic information system quantified the visual exposure of respective ponds to humans. Binary classification trees were developed as a function of their visibility from roads, as well as five environmental factors: river density, connectivity with upstream dam reservoirs, pond area, chlorophyll a concentration, and pond drainage. Traditional indicators of human-mediated introduction (road density and proportion of urban land-use area) were alternatively included for comparison instead of visual exposure. The presence of Bluegill (Lepomis macrochirus) was predicted by the ponds' higher visibility from roads and pond connection with upstream dam reservoirs. Results suggest that fish stocking into ponds and their dispersal from upstream sources facilitated species establishment. Largemouth bass (Micropterus salmoides) distribution was constrained by chlorophyll a concentration, suggesting their lower adaptability to various environments than that of Bluegill. Based on misclassifications from classification trees for Bluegill, pond visual exposure to roads showed greater predictive capability than traditional indicators of human-mediated introduction. Pond visibility is an effective predictor of invasive species distribution. Its wider use might improve management and mitigate further invasion. The visual exposure of recipient ecosystems to humans is important for many invasive species that

  6. High-temperature treatment for efficient drying of bread rye and reduction of fungal contaminants

    DEFF Research Database (Denmark)

    Kristensen, E.F.; Elmholt, S.; Thrane, Ulf

    2005-01-01

    on the grain. The aim of this study was to establish a drying regime that kills fungal propagules on rye without reducing its quality for baking. Special attention was paid to some important mycotoxin-producing species. As drying temperatures and retention time in the drum are essential, the drum drier must...... the grain was properly stored afterwards. At the same time a high quality for baking was maintained. The highest baking quality in rye was obtained at grain temperatures of about 62 degrees C and only at grain temperatures above 70 degrees C visual quality changes were detected. (c) 2005 Silsoe Research...

  7. Sphagnum farming in Germany – a review of progress

    Directory of Open Access Journals (Sweden)

    G. Gaudig

    2014-02-01

    Full Text Available In ombrotrophic, nutrient-poor peatlands, the cultivation of peatmoss (Sphagnum spp. is a promising paludiculture option. Since 2001 we have been studying peatmoss cultivation (‘Sphagnum farming’ in greenhouse and field experiments, paying special attention to propagation, propagule storage, establishment, productivity and regeneration. Our studies show that Sphagnum farming in Germany may provide a sustainable high-quality alternative to fossil white peat as a raw material for horticultural growing media. Sphagnum farming is, furthermore, a climate-friendly and sustainable land use option for abandoned cut-over bogs and degraded bog grassland.

  8. Clonal propagation of eucalyptus by tissue culture

    Energy Technology Data Exchange (ETDEWEB)

    Mehra-Palta, A.

    1982-07-01

    Multiple adventitious buds were induced on cotyledons, shoot tips and nodal stem segments of Eucalyptus species cultured on a defined nutrient medium supplemented with the cytokinin zeatin and the auxin indole-3-butyric acid (IBA). The adventitious buds could be recycled on cytokinin medium to produce more buds thus providing the possibility of producing large clones from selected genotypes. The adventitious shoots were rooted in auxin medium and some of the resulting propagules were outplanted in the field. These techniques have the potential for use in the genetic improvement of Eucalyptus. (Refs. 15).

  9. Effects of band-steaming on microbial activity and abundance in organic farming soil

    DEFF Research Database (Denmark)

    Elsgaard, Lars; Jørgensen, Martin Heide; Elmholt, Susanne

    2010-01-01

    Band-steaming of arable soil at 80-90 ◦C kill off weed seeds prior to crop establishment which allows an extensive intra-row weed control. Here we evaluated the side-effects of in situ band-steaming on soil respiration, enzyme activities, and numbers of culturable bacteria and fungi in an organic...... insignificant or slightly stimulatory (P recovery during 90 days after band-steaming. Bacterial colony-forming units increased after soil steaming...... whereas the number of fungal propagules was reduced by 50% (P recovery potential...

  10. Combining mechanical rhizome removal and cover crops for Elytrigia repens control in organic barley systems

    DEFF Research Database (Denmark)

    Melander, B; Nørremark, M; Kristensen, E F

    2013-01-01

    of vegetative propagules located within the plough layer to allow for quick re-establishment of a plant cover. A field experiment comparing the effects of conventional practices (stubble cultivation) with different combinations of rotary cultivation (One, Two or four passes) and cover crops (none vs. rye......-vetch-mustard mixture) on Elytrigia repens rhizome removal, shoot growth and suppression of a subsequent barley crop was examined in two growing seasons. Four passes with a modified rotary cultivator, where each pass was followed by rhizome removal, reduced E. repens shoot growth in barley by 84% and 97%. In general...

  11. Bacteria obtained from a sequencing batch reactor that are capable of growth on dehydroabietic acid.

    OpenAIRE

    Mohn, W W

    1995-01-01

    Eleven isolates capable of growth on the resin acid dehydroabietic acid (DhA) were obtained from a sequencing batch reactor designed to treat a high-strength process stream from a paper mill. The isolates belonged to two groups, represented by strains DhA-33 and DhA-35, which were characterized. In the bioreactor, bacteria like DhA-35 were more abundant than those like DhA-33. The population in the bioreactor of organisms capable of growth on DhA was estimated to be 1.1 x 10(6) propagules per...

  12. Deteksi Keberadaan Phytophthora Spp. Di Air

    OpenAIRE

    Sulistyawati, Purnamila

    2014-01-01

    The genus of Phytophthora is a destructive plants pathogen. However the existence of these species in plant tissue was hardly to detect because the fungus may also be present as resistant propagules in soil or spread through waterways. This study aimed to test the FTA card as a direct bait to obtain the DNA of Phytophthora spp and also to investigate the suitability of FTA card as a sampling method. This research used several Phytophthora baits including FTA card followed by DNA extraction a...

  13. Fungal Endophyte Diversity and Bioactivity in the Indian Medicinal Plant Ocimum sanctum Linn.

    Directory of Open Access Journals (Sweden)

    Kanika Chowdhary

    Full Text Available Endophytic mycopopulation isolated from India's Queen of herbs Tulsi (Ocimum sanctum were explored and investigated for their diversity and antiphytopathogenic activity against widespread plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani and Fusarium oxysporum. 90 fungal isolates, representing 17 genera were recovered from 313 disease-free and surface sterilised plant segments (leaf and stem tissues from three different geographic locations (Delhi, Hyderabad and Mukteshwar during distinct sampling times in consequent years 2010 and 2011 in India. Fungal endophytes were subjected to molecular identification based on rDNA ITS sequence analysis. Plant pathogens such as F. verticillioides, B. maydis, C. coarctatum, R. bataticola, Hypoxylon sp., Diaporthe phaseolorum, Alternaria tenuissima and A. alternata have occurred as endophyte only during second sampling (second sampling in 2011 in the present study. Bi-plot generated by principal component analysis suggested tissue specificity of certain fungal endophytes. Dendrogram revealed species abundance as a function of mean temperature of the location at the time of sampling. Shannon diversity in the first collection is highest in Hyderabad leaf tissues (H' = 1.907 whereas in second collection it was highest from leaf tissues of Delhi (H' = 1.846. Mukteshwar (altitude: 7500 feet reported least isolation rate in second collection. Nearly 23% of the total fungal isolates were considered as potent biocontrol agent. Hexane extract of M. phaseolina recovered from Hyderabad in first collection demonstrated highest activity against S. sclerotiorum with IC50 value of 0.38 mg/ml. Additionally, its components 2H-pyran-2-one, 5,6-dihydro-6-pentyl and palmitic acid, methyl ester as reported by GC-MS Chromatogram upon evaluation for their antiphytopathogenic activity exhibited IC50 value of 1.002 and 0.662 against respectively S. sclerotiorum indicating their significant role in

  14. Viable allergenic fungi in a documentary deposit of the National Archive of Cuba

    Directory of Open Access Journals (Sweden)

    Alian Molina-Veloso

    2017-02-01

    Full Text Available Background: Intense and persistent exposure to indoor-air biological agents has been associated with the appearance of allergic diseases. Archives and libraries Indoor environments in tropical countries are an important reservoir of fungal propagules. Objective: To evaluate the degree of air pollution with allergenic fungi in a repository of frequently-manipulated documents. Methods: Air sampling was performed by two methods: active (biocollector and passive (sedimentation plate. Fungi were taxonomically identified, and spores were measured to determine their penetrability in the human respiratory tract, and its impact on episodes of allergy. Results: In terms of concentration and diversity, the local environment behaved as a fungal propagule reservoir, which showed that there is significant health risk for the staff that manipulates the documents. Some spores were shown to be able to reach the lower respiratory tract when inhaled, which increases their allergenic and pathogenic potential. Aspergillus, Cladosporium, Penicillium and Alternaria, which are referred to as highly allergenic fungi, were prevalent. Conclusion: Aerobiological studies are a valuable tool for the treatment of patients with allergy to fungi and other disorders they produce.

  15. Post-spill behavior in an Oil Contaminated Mangrove Stand Avicennia Marina (Forssk.) Vierh in UAE

    International Nuclear Information System (INIS)

    Youssef, T.; El-Amry, M.; Youssef, A.

    2000-01-01

    The effect of post-spill defoliation and the subsequent readjustment in resource allocation was investigated in relation to individual reproductive fitness of the monotypic mangrove stands Avicennia mariana in Umm Al-Qwain Bay, northeastern United Arab Emirates. The effects of persistence of high levels of oil hydrocarbons in the sediments after the spill on propagule dispersal, seedling recruitment, and anomalous vegetative growth forms were also studied. Growth and physiological performance of the new individuals produced from polluted and unpolluted vegetations were compared under glasshouse conditions. Vegetative recovery of oil mangrove stands from post-spill massive defoliation had a negative effect on all stages of plant reproductive events including flowering, fruiting and propagule dispersal. Persistence of toxic levels of oil hydrocarbons in the substrate has further reduced the possibility of successful establishment of new generation in the contaminated site. A significant correlation exists between the levels of hydrocarbons in the sediments and the degree of anomalies in shoot growth of seedlings (r=0.862) and the newly growing pneumataphores (r=0.827). Improving substrate condition by reducing levels of toxic hydrocarbons would increase the chance for better recruitment and performance of the new generation of seedlings. Active rehabilitation processes at the site may enhance the site productivity and minimize time for natural recovery. (author)

  16. Evaluation of mangrove reforestation and the impact to socioeconomic-cultural of community in Lubuk Kertang village, North Sumatra

    Science.gov (United States)

    Basyuni, M.; Harahap, MA; Wati, R.; Slmaet, B.; Thoha, AS; Nuryawan, A.; Putri, LAP; Yusriani, E.

    2018-03-01

    Mangrove forests in North Sumatera existed in the east coast of Sumatera Island and are rapidly threatened due to anthropogenic activities such as conversion for aquaculture, oil palm plantation, filling and use of mangrove for urban development. The present study describes the current and first-year evaluation on mangrove restoration and its impact to socio economic-cultural of community in Lubuk Kertang village, Langkat, North Sumatra, Indonesia. The rehabilitation was carried on December 2015 using direct planting of 6,000 Rhizophora apiculata propagules and May 2016 using 5,000 R. apiculata seedlings. The evaluation parameters of mangrove reforestation consist of seedling diameter and height, leaf thickness and number, and seedling growth rate. Ninety-two of 1,124 households were surveyed using Slovin formula to obtain community perspective on the socio-economic-cultural impact of reforestation. Results show that the growth rate for current and first-year evaluation was 93 and 86 %, respectively. By contrast, the height, diameter, and some leaves seedlings planting were shown better than the performance of propagules planting. No change in the green foliage plant thickness between both farming methods. The reforestation affected 71.74, 55.43 and 39.13% of economic, social, and cultural of Lubuk Kertang community, respectively. The data is likely to provide valuable information for mangrove reforestation in North Sumatra.

  17. Comparative analysis of seed rain of Gaiadendron punctatum (Ruiz and Pavon) G. Don (loranthaceae) and Ternstroemia meridionalis mutis ex l.f. (theaceae) at natural municipal park Rancheria (Boyaca), Colombia

    International Nuclear Information System (INIS)

    Parada Quintero, Martha

    2012-01-01

    Gaiadendron punctatum (Ruiz and Pavon) G. Don and Ternstroemia meridionalis mutis ex l.f. are ornithochorous species of the high Andean forest; the first is abundant at natural municipal park Rancheria and the second rare at local level. The seed rain and fruiting phenology of G. punctatum and T. meridionalis were evaluated. Records were kept between March and December of 2010. This period included dry and wet seasons. Eight traps with a recollection surface of 1 m 2 were installed. Fruiting of G. punctatum and T. meridionalis was continued with a high percentage of unripe fruits. The higher fruiting was shown in the wet season. Both species presented seed rain during all the study. G. punctatum had higher seed rain with an average of 169/m 2 ; while t. meridionalis only 50 seeds/m 2 . Most abundance of G. punctatums seeds was recorded in the dry season, while for T. meridionalis in wet season. In spite of low seed rain for T. meridionalis it showed a high percentage of viable seeds. G. punctatum presented more propagules that could explain the high number of individuals by area. Although the number of seeds of T. meridionalis is not very high, it represents a potential for prevalence of this specie and the need of looking for factors that to block the persistence of this propagules.

  18. Bounded and unbounded boundaries - Untangling mechanisms for estuarine-marine ecological connectivity: Scales of m to 10,000 km - A review

    Science.gov (United States)

    Wolanski, Eric

    2017-11-01

    Recent advances in our understanding of the self-recruitment and connectivity of estuarine and coastal fauna and flora were made possible by an integration of physical oceanographic observations and modelling with results from studies of the behaviour of the seeds, eggs, larvae, propagules, juveniles and polyps, of population dynamics, microchemical tagging using natural and artificial markers, genetics and direct observations of trajectories. The species studied in those case studies were jellyfish in marine lakes, corals in acidified bays, seagrass, mangrove propagules, mussels and oysters, prawns, some estuarine fish larvae, the copepod Calanus finmarchius in the North Sea, sea turtles in the Coral Sea, and the ornate spiny lobster Panulirus ornatus in the Southeast Asia archipelago. The spatial scales for self-recruitment and connectivity vary with the species from a few m to 10,000 km, and the temporal scales vary from one to three generations. These studies suggest that, with increasing physical openness of a given site for a given species, self-recruiting increasingly relies on the behaviour of the species. Estuarine and coastal systems thus are simultaneously bounded and unbounded depending on the sites and the species considered and, although often ignored, the integration of oceanographic and behavioural understanding is increasingly required. This paper has shown the importance of understanding the hydrological and ecological dynamics with unbounded boundaries in creating the connectivity between parts of the aquatic continuum from the river catchment to the open seas.

  19. Growth in liverworts of the Marchantiales is promoted by epiphytic methylobacteria

    Science.gov (United States)

    Kutschera, U.; Koopmann, V.

    2005-07-01

    Liverworts, the most basal lineage of extant land plants, have been used as model systems in the reconstruction of adaptations to life on land. In this study, we used gemmae (specialized propagules) that were isolated from mature gemma cups of two distantly related species of liverworts, Marchantia polymorpha L. and Lunularia cruciata L. (order Marchantiales). We show that methylobacteria (genus Methylobacterium), microbes that inhabit the surfaces of land plants where they secrete phytohormones (cytokinines), promote the growth of isolated gemmae cultivated on agar plates. As a control, two species of higher plants, maize (Zea mays L.) and sunflower (Helianthus annuus L.) were raised aseptically from sterile seeds (i.e., caryopses, achenes). Inoculation of these propagules with methylobacteria was without effect on growth in the above-ground phytosphere (expansion of stems and leaves). We conclude that normal development in Marchantia and Lunularia is dependent on (and possibly regulated by) epiphytic methylobacteria, whereas representative higher plants grow at optimal rates in the absence of these prokaryotic epiphytes.

  20. A laboratory simulation of the carbonization of sunflower achenes and seeds

    Energy Technology Data Exchange (ETDEWEB)

    Braadbaart, F. [FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam (Netherlands); Department of Earth Sciences-Geochemistry, Faculty of Geosciences, Utrecht University, P.O. Box 80021, 3058 TA Utrecht (Netherlands); Wright, P.J. [Department of Anthropology, University of Missouri-St. Louis, St. Louis, MO 63121 (United States); Horst, J. van der; Boon, J.J. [FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam (Netherlands)

    2007-03-15

    The current project describes physical and chemical alterations that result from the thermal exposure of sunflower achenes and seeds. Specifically, achenes and seeds were heated at temperatures ranging from 130 to 600 C under anoxic conditions for 60 min. Changes were measured in mass, relative percentages of C and N, internal and external morphology, molecular composition by direct temperature-resolved mass spectrometry (DTMS) under EI conditions, and the reflectance on polished specimens. The main constituents of sunflower seeds are lipids and protein, while the pericarps or hulls enclosing the seeds have a ligno-cellulosic structure. The morphology of achenes and seeds remains intact following exposure which makes the identification of the residues possible. The results of the sunflower experiments were compared to previous experiments conducted with peas and wheat grains. Up to approximately 340 C, the molecular conversion of polysaccharide and protein rich peas and wheat grains follow similar pathways, while the lignin present in sunflower achenes follows its own unique pathway, resulting in a different molecular composition. At higher temperatures the molecular composition of the three propagules becomes identical. In addition the reflectance of the three propagules is identical confirming the similarity in molecular composition. Lipids show a different behaviour compared to the other three biopolymers; from 370 C no oils are observed in the heated specimens and the DTMS-EI measurements show no lipid markers. Apart from evaporation of the triacylglycerides it is suggested that steroids have a high resistance against thermal degradation and are converted into aromatic moieties. (author)

  1. Direct quantification of fungal DNA from soil substrate using real-time PCR.

    Science.gov (United States)

    Filion, Martin; St-Arnaud, Marc; Jabaji-Hare, Suha H

    2003-04-01

    Detection and quantification of genomic DNA from two ecologically different fungi, the plant pathogen Fusarium solani f. sp. phaseoli and the arbuscular mycorrhizal fungus Glomus intraradices, was achieved from soil substrate. Specific primers targeting a 362-bp fragment from the SSU rRNA gene region of G. intraradices and a 562-bp fragment from the F. solani f. sp. phaseoli translation elongation factor 1 alpha gene were used in real-time polymerase chain reaction (PCR) assays conjugated with the fluorescent SYBR(R) Green I dye. Standard curves showed a linear relation (r(2)=0.999) between log values of fungal genomic DNA of each species and real-time PCR threshold cycles and were quantitative over 4-5 orders of magnitude. Real-time PCR assays were applied to in vitro-produced fungal structures and sterile and non-sterile soil substrate seeded with known propagule numbers of either fungi. Detection and genomic DNA quantification was obtained from the different treatments, while no amplicon was detected from non-seeded non-sterile soil samples, confirming the absence of cross-reactivity with the soil microflora DNA. A significant correlation (Pgenomic DNA of F. solani f. sp. phaseoli or G. intraradices detected and the number of fungal propagules present in seeded soil substrate. The DNA extraction protocol and real-time PCR quantification assay can be performed in less than 2 h and is adaptable to detect and quantify genomic DNA from other soilborne fungi.

  2. Ship traffic and the introduction of diatoms and dinoflagellates via ballast water in the port of Annaba, Algeria

    Science.gov (United States)

    Cheniti, Radhia; Rochon, André; Frihi, Hocine

    2018-03-01

    We present here the first study on the role of ship traffic in the introduction of potentially harmful and/or non-indigenous species in the port of Annaba (Algeria). A total of 25 ships of two different types (general cargo and bulk carriers) were sampled and separated into two categories: oceanic and Mediterranean ships. We estimated propagule pressure of high-risk coastal phytoplankton delivered in ballast water to the port of Annaba. We identified 40 diatom and 38 dinoflagellate taxa, among which, 11 harmful/toxic taxa: Pseudo-nitzschia spp., Alexandrium tamarense, Alexandrium sp., Dinophysis acuminata, Dinophysis rotundata, Dinophysis sp., Gonyaulax spinifera, Gymnodinium catenatum, Lingulodinium polyedrum, Protoceratium reticulatum and cyst of Alexandrium sp. In addition, 8 taxa (5 diatoms, 1 dinoflagellate and 2 dinoflagellate cysts) never observed in the Annaba region were considered as potentially non-indigenous: Actinoptychus splendens, Coscinodiscus asteromphalus, Coscinodiscus lineatus, Odentella granulata, Thalassiosira cf. decipiens, Prorocentrum scutellum, cyst of Polykrikos kofoidii and Islandinium minutum. Several factors were examined, including ship routes, ballast water age and the volume of ballast water discharged. Our analyses revealed that diatom and dinoflagellate abundances decreased with ballast water age, possibly as a result of mortality of species due to voyage length and lack of light in ballast tanks. Estimates of actual propagule pressure, diatoms and dinoflagellates abundances varied from 1 to 4 × 108 cells/ship. The results of this study could serve as the baseline for the development and implementation of monitoring and ballast water management programs in ports of Algeria.

  3. Biochemical markers assisted screening of Fusarium wilt resistant Musa paradisiaca (L.) cv. puttabale micropropagated clones.

    Science.gov (United States)

    Venkatesh; Krishna, V; Kumar, K Girish; Pradeepa, K; Kumar, S R Santosh; Kumar, R Shashi

    2013-07-01

    An efficient protocol was standardized for screening of panama wilt resistant Musa paradisiaca cv. Puttabale clones, an endemic cultivar of Karnataka, India. The synergistic effect of 6-benzyleaminopurine (2 to 6 mg/L) and thidiazuron (0.1 to 0.5 mg/L) on MS medium provoked multiple shoot induction from the excised meristem. An average of 30.10 +/- 5.95 shoots was produced per propagule at 4 mg/L 6-benzyleaminopurine and 0.3 mg/L thidiazuron concentrations. Elongation of shoots observed on 5 mg/L BAP augmented medium with a mean length of 8.38 +/- 0.30 shoots per propagule. For screening of disease resistant clones, multiple shoot buds were mutated with 0.4% ethyl-methane-sulfonate and cultured on MS medium supplemented with Fusarium oxysporum f. sp. cubense (FOC) culture filtrate (5-15%). Two month old co-cultivated secondary hardened plants were used for screening of disease resistance against FOC by the determination of biochemical markers such as total phenol, phenylalanine ammonia lyase, oxidative enzymes like peroxidase, polyphenol oxidase, catalase and PR-proteins like chitinase, beta-1-3 glucanase activities. The mutated clones of M. paradisiaca cv. Puttabale cultured on FOC culture filtrate showed significant increase in the levels of biochemical markers as an indicative of acquiring disease resistant characteristics to FOC wilt.

  4. Biological Control of Fusarium oxysporum f.sp. cumini with Aspergillus versicolor

    Directory of Open Access Journals (Sweden)

    S. Israel

    2005-04-01

    Full Text Available A native heat-tolerant strain of Aspergillus versicolor (Vuill. Tirab. highly antagonistic to Fusarium oxysporum f. sp. cumini (Foc was isolated from arid soils. In tests performed to ascertain its antagonistic activity against Foc as compared to Trichoderma harzianum, a 99.2 and 96.4% reduction in Foc propagules was achieved in A. versicolor and T. harzianum infested soil respectively. The reduction of Foc propagules in Foc and A. versicolorinfested soil was also determined. In a liquid-culture test, even at a low concentration of 0.5 ml cell-free filtrate, A. versicolor inhibited mycelial growth of Foc. Population changes of A. versicolor were examined at different soil moisture gradients, where maximum survival and multiplication of A. versicolor was estimated at 50% of moisture holding capacity. In general, with increasing concentrations of A. versicolor inoculum, soil population densities of Foc went down. Studies on thermal resistance showed that A. versicolor survived and multiplied even at 65°C. Soil amended with A. versicolor alone, or with a combination of T. harzianum and Verbisina enceloides residues was significantly better at reducing Foc than was non-amended control soil. A marked increase in the root length of cumin was observed in soil amended with A. versicolor or T. harzianum or both. The results suggest that A. versicolor has a potential value for use against Fusarium in hot arid soils because it can survive under dry and high-temperature conditions.

  5. In vitro propagation of sacaca (Croton cajucara: insights about difficulties for developing micropropagation protocols

    Directory of Open Access Journals (Sweden)

    Tatiane Loureiro da Silva

    2015-12-01

    Full Text Available Sacaca is a medicinal plant from the Amazonian biome and it has been regarded as a substitute for rosewood (Aniba roseaodora to produce linalool. This paper aimed to evaluate in vitro vegetative propagation of sacaca, including the establishment of propagules from the field, decontamination protocols, and determination of multiplication rates, besides describing limiting aspects for the culture during in vitro experiments. We used 1.0 cm microcuttings with an axillary bud, collected from adult plants in the field. Disinfestation treatments were tested in the establishment, and there is an evaluation of the collecting month influence on the contamination rates. After disinfestation, microcuttings were placed in test tubes containing MS medium, added with BAP (0, 1, 2 and 3 mg L-1 and GA3 (0 and 0.5 mg L-1. In vitro establishment of sacaca with 41.9% of sprouted microcuttings was obtained. The contamination rate reached 58.1% (65.4% caused by fungi and 34.6% by bacteria, with greater occurrence when propagules were collected between October and January, the rainiest months in the Amazon region. The increased BAP and GA3 concentrations in the culture medium provided significant improvements in the material multiplication rates. In spite of the results obtained, the species shows peculiarities and limitations to in vitro cultivation that were identified and described in this paper.

  6. OCCURRENCE IN THE SOIL AND DISPERSAL OF Lecanicillium lecanii, A FUNGAL PATHOGEN OF THE GREEN COFFEE SCALE (Coccus viridis AND COFFEE RUST (Hemileia vastatrix

    Directory of Open Access Journals (Sweden)

    Doug William Jackson

    2012-08-01

    Full Text Available The fungus Lecanicillium lecanii attacks the green scale (Coccus viridis, a pest of coffee, and is also a hyperparasite of coffee rust (Hemileia vastatrix. Knowledge of the epizootiology of this fungus is potentially important for conservation biological control in coffee agroecosystems. The presence of viable propagules of L. lecanii in the soil, a possible environmental reservoir, was assessed using two baiting methods: the standard Galleria mellonella bait method and a C. viridis bait method. Infectious propagules of L. lecanii were detected in soil samples taken from a 45 ha study plot, both nearby and far from recent epizootics of L. lecanii. To test the potential for the transmission of L. lecanii conidia from the soil via rain splash or wind, coffee seedlings with populations of C. viridis were placed near L. lecanii-inoculated soil and then subjected to artificial rain and wind treatments. Rain splash was shown to be a potential transmission mechanism. Dispersal of L. lecanii conidia by the ant Azteca instabilis was tested using field and laboratory ant-exclusion experiments. Azteca instabilis was shown to transport conidia of L. lecanii; however, dispersal by A. instabilis may not be important under field conditions.

  7. Amplified recruitment pressure of biofouling organisms in commercial salmon farms: potential causes and implications for farm management.

    Science.gov (United States)

    Bloecher, Nina; Floerl, Oliver; Sunde, Leif Magne

    2015-01-01

    The development of biofouling on finfish aquaculture farms presents challenges for the industry, but the factors underlying nuisance growths are still not well understood. Artificial settlement surfaces were used to examine two possible explanations for high rates of biofouling in Norwegian salmon farms: (1) increased propagule release during net cleaning operations, resulting in elevated recruitment rates; and (2) potential reservoir effects of farm surfaces. The presence of salmon farms was associated with consistently and substantially (up to 49-fold) elevated recruitment rates. Temporal patterns of recruitment were not driven by net cleaning. Resident populations of biofouling organisms were encountered on all submerged farm surfaces. Calculations indicate that a resident population of the hydroid Ectopleura larynx, a major biofouling species, could release between 0.3 × 10(9) and 4.7 × 10(9) larvae per farm annually. Such resident populations could form propagule reservoirs and be one explanation for the elevated recruitment pressure at salmon farms.

  8. Prevention of the bad dry of the malanga by treatment of natural, biological origin

    Directory of Open Access Journals (Sweden)

    Michel Chamizo Nicao

    2014-04-01

    Full Text Available One of the most important causes of the decrease of yields in taro crops (Xanthosoma spp. isthe roots rot caused by soil fungi (Bad dry which it’s propagated by the agamic seed used as propagules. One of the most important measures to prevent it is the use of “in vitro” plants free of fungi. In this research was studied the incorporation of several natural and biological products in the plots employed to acclimatize the “invitro” plants. Were evaluated: Trichoderma harzianum, Chitosan, and lobster shell ( Panulirus argus (Latreilleand as control Mancozeb. The taro cultivars employed were Blanca INIVIT and Blanca Venegas, considerate as intermediated and susceptible respectively. Each plot was inoculated with propagules of Sclerotium rolsfii (Sacc.. In order to infer the action mechanism was conducted susceptible tests under “in vitro” conditions. The results showed that the most susceptible cultivar was Blanca Venegas. All treatments decrease the incidence of dry rot, among these. T. harzianum produced the highest effect, antagonist capacity and antagonist effect type. The Chitosan and the lobster shell do not showed antifungal direct effect and probably act for stimulation of the protein synthesis related with the pathogenesis or structural barrier of defense in natural conditions.

  9. Inferring differential evolutionary processes of plant persistence traits in Northern Hemisphere Mediterranean fire-prone ecosystems

    Science.gov (United States)

    Pausas, J.G.; Keeley, J.E.; Verdu, M.

    2006-01-01

    1 Resprouting capacity (R) and propagule-persistence (P) are traits that are often considered to have evolved where there are predictable crown fires. Because several indicators suggest a stronger selective pressure for such traits in California than in the Mediterranean Basin, we hypothesize that plant species should have evolved to become R+ and P+ more frequently in California than in the Mediterranean Basin. 2 To test this hypothesis we studied the phylogenetic association between R and P states in both California and the Mediterranean Basin using published molecular phylogenies. 3 The results suggest that R and P evolved differently in the two regions. The occurrence of the states differs significantly between regions for trait P, but not for trait R. The different patterns (towards R+ and P+ in California and towards R+ and P- in the Mediterranean Basin) are reflected in the higher abundance and the wider taxonomic distribution of species with both persistence traits (R+P+ species) in California. 4 The differential acquisition of fire persistence mechanisms at the propagule level (P+) supports the idea that fire selective pressures has been higher in California than in the Mediterranean Basin. 5 Our comparative phylogenetic-informed analysis contributes to an understanding of the differential role of the Quaternary climate in determining fire persistence traits in different Mediterranean-type ecosystems and, thus, to the debate on the evolutionary convergence of traits. ?? 2006 British Ecological Society.

  10. In vitro propagation of sacaca (Croton cajucara: insights about difficulties for developing micropropagation protocols

    Directory of Open Access Journals (Sweden)

    Tatiane Loureiro da Silva

    2015-09-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2015v28n4p41 Sacaca is a medicinal plant from the Amazonian biome and it has been regarded as a substitute for rosewood (Aniba roseaodora to produce linalool. This paper aimed to evaluate in vitro vegetative propagation of sacaca, including the establishment of propagules from the field, decontamination protocols, and determination of multiplication rates, besides describing limiting aspects for the culture during in vitro experiments. We used 1.0 cm microcuttings with an axillary bud, collected from adult plants in the field. Disinfestation treatments were tested in the establishment, and there is an evaluation of the collecting month influence on the contamination rates. After disinfestation, microcuttings were placed in test tubes containing MS medium, added with BAP (0, 1, 2 and 3 mg L-1 and GA3 (0 and 0.5 mg L-1. In vitro establishment of sacaca with 41.9% of sprouted microcuttings was obtained. The contamination rate reached 58.1% (65.4% caused by fungi and 34.6% by bacteria, with greater occurrence when propagules were collected between October and January, the rainiest months in the Amazon region. The increased BAP and GA3 concentrations in the culture medium provided significant improvements in the material multiplication rates. In spite of the results obtained, the species shows peculiarities and limitations to in vitro cultivation that were identified and described in this paper.

  11. The effect of consumers and mutualists of Vaccinium membranaceum at Mount St. Helens: dependence on successional context.

    Directory of Open Access Journals (Sweden)

    Suann Yang

    Full Text Available In contrast to secondary succession, studies of terrestrial primary succession largely ignore the role of biotic interactions, other than plant facilitation and competition, despite the expectation that simplified interaction webs and propagule-dependent demographics may amplify the effects of consumers and mutualists. We investigated whether successional context determined the impact of consumers and mutualists by quantifying their effects on reproduction by the shrub Vaccinium membranaceum in primary and secondary successional sites at Mount St. Helens (Washington, USA, and used simulations to explore the effects of these interactions on colonization. Species interactions differed substantially between sites, and the combined effect of consumers and mutualists was much more strongly negative for primary successional plants. Because greater local control of propagule pressure is expected to increase successional rates, we evaluated the role of dispersal in the context of these interactions. Our simulations showed that even a small local seed source greatly increases population growth rates, thereby balancing strong consumer pressure. The prevalence of strong negative interactions in the primary successional site is a reminder that successional communities will not exhibit the distribution of interaction strengths characteristic of stable communities, and suggests the potential utility of modeling succession as the consequence of interaction strengths.

  12. The movement ecology of seagrasses.

    Science.gov (United States)

    McMahon, Kathryn; van Dijk, Kor-Jent; Ruiz-Montoya, Leonardo; Kendrick, Gary A; Krauss, Siegfried L; Waycott, Michelle; Verduin, Jennifer; Lowe, Ryan; Statton, John; Brown, Eloise; Duarte, Carlos

    2014-11-22

    A movement ecology framework is applied to enhance our understanding of the causes, mechanisms and consequences of movement in seagrasses: marine, clonal, flowering plants. Four life-history stages of seagrasses can move: pollen, sexual propagules, vegetative fragments and the spread of individuals through clonal growth. Movement occurs on the water surface, in the water column, on or in the sediment, via animal vectors and through spreading clones. A capacity for long-distance dispersal and demographic connectivity over multiple timeframes is the novel feature of the movement ecology of seagrasses with significant evolutionary and ecological consequences. The space-time movement footprint of different life-history stages varies. For example, the distance moved by reproductive propagules and vegetative expansion via clonal growth is similar, but the timescales range exponentially, from hours to months or centuries to millennia, respectively. Consequently, environmental factors and key traits that interact to influence movement also operate on vastly different spatial and temporal scales. Six key future research areas have been identified.

  13. Use of homeopathic drugs in combination with fertilizers for the control of root rot fungi

    International Nuclear Information System (INIS)

    Hanif, A.; Dawar, S.

    2015-01-01

    This study was conducted to evaluate the fungicidal effectiveness of homeopathic drugs in combination with fertilizers on the growth production and controlling of root rot fungi. Seeds treated with homeopathic drugs in addition of phosphorous and nitrogen fertilizers as soil amendment showed significant inhibitory effect on fungal growth as well as improved the plant growth. Remarkable control of root infecting fungi was shown by the seeds treated with Thuja occidentalis and Arnica montana at rate of 75 percentage v/v concentration and soil amended with urea at rate of 0.1 percentage w/w but greater increased in plant growth was observed by urea at rate of 0.01 percentage in the tested plants viz. mung bean, mash bean, sunflower and okra. Whereas, when A. montana and T. occidentalis at rate of 75 percentage v/v concentration along with the addition of DAP at rate of 0.01 and 0.1 percentage w/w respectively showed maximum suppression of Fusarium spp, R. solani and M. phaseolina and enhanced the plant height and weight followed by A. montana and T. occidentalis at rate of 50 percentage v/v concentration respectively showed a maximum control of root rot fungi and also strengthened the crop plant for better growth. (author)

  14. Physiological aspects of fungi isolated from root nodules of faba bean (Vicia faba L.).

    Science.gov (United States)

    Omar, S A; Abd-Alla, M H

    2000-03-01

    The present study was made to isolate and assess some physiological characteristics of root nodule-colonizing fungi. During this study, 17 fungal species were isolated from root nodule samples taken from faba bean plants (Vicia faba L.) collected from different sites at Assiut area (Egypt). The growth of faba bean plants in pots was significantly promoted by soil inoculation with most fungi. Growth was checked in pots with inocula of Cladosporium cladosporioides, Fusarium moniliforme, F: oxysporium, F solani, Macrophominia phaseolina and Rhizoctonia solani which were added separately. All growth-promoting fungi were capable of producing cellulase, pectin lyase, polygalacturonase, protease, urease, amidase, acid phosphatase, alkaline phosphatase and arylsulfatase in growth medium supplemented with the corresponding substrates. Four fungal species, Aspergillus awamori, A. flavus, Penicillium chrysogenum and Trichoderma koningii showed the highest rates of enzyme formation. The effect of the addition of six trace elements to the growth media at 30 micromol/ml on enzyme production revealed some dependency on species, enzyme and metal ion. Cd2+, Hg2+ and Zn2+ generally inhibited enzyme activity. Cu(1+), Fe3+ and Al3+ showed a stimulatory effect. Fungicides (afugan and tilt) and herbicides (brominal and fusilade) at 50 ppm generally promoted enzyme activity, but insecticides (kelthane and fenvalerate) caused some inhibition to enzyme activities. Salinization of the growth media with NaCl strongly inhibited the enzymatic activity of all fungi at concentrations between 0.5 and 1.5%.

  15. La collection de base des espèces sauvages de Phaseolus et Vigna : historique, gestion et conservation

    Directory of Open Access Journals (Sweden)

    Thierry Vanderborght

    1998-01-01

    Full Text Available The base collection of wild species of Phaseolus and Vigna: history, management and conservation.The National Botanic Garden of Belgium ensures the management of a base collection of botanical and wild forms in the tribe Phaseoleae and the sub-tribe Phaseolinae. The main objective is to conserve on a long terni basic the largest possible genetic diversity through seed semples stored at - 20°C. The collection provided the basic material for the investigations conducted at the University Faculty of Agricultural Sciences of Gembloux in fields as diverse as taxonomy, genome analysis, definition of genetic réservoirs, agronomie and chemical evaluations, interspecific hybridization and plant breeding. The results have allowed to becter understand the organization of genetic diversity in the studied plant material and to highlight the wealthy genetic potentiel of the collection. The latter should be preserved and valorized for the genetic improvement of food legumes, in particular within the two genera Phaseolus and Vigna.

  16. Potential biocontrol actinobacteria: Rhizospheric isolates from the Argentine Pampas lowlands legumes.

    Science.gov (United States)

    Solans, Mariana; Scervino, Jose Martin; Messuti, María Inés; Vobis, Gernot; Wall, Luis Gabriel

    2016-11-01

    Control of fungal plant diseases by using naturally occurring non-pathogenic microorganisms represents a promising approach to biocontrol agents. This study reports the isolation, characterization, and fungal antagonistic activity of actinobacteria from forage soils in the Flooding Pampa, Argentina. A total of 32 saprophytic strains of actinobacteria were obtained by different isolation methods from rhizospheric soil of Lotus tenuis growing in the Salado River Basin. Based on physiological traits, eight isolates were selected for their biocontrol-related activities such as production of lytic extracellular enzymes, siderophores, hydrogen cyanide (HCN), and antagonistic activity against Cercospora sojina, Macrophomia phaseolina, Phomopsis sp., Fusarium oxysporum, and Fusarium verticilloides. These actinobacteria strains were characterized morphologically, physiologically, and identified by using molecular techniques. The characterization of biocontrol-related activities in vitro showed positive results for exoprotease, phospholipase, fungal growth inhibition, and siderophore production. However, none of the strains was positive for the production of hydrogen cyanide (HCN). Streptomyces sp. MM140 presented the highest index for biocontrol, and appear to be promising pathogenic fungi biocontrol agents. These results show the potential capacity of actinobacteria isolated from forage soils in the Argentine Pampas lowlands as promising biocontrol agents, and their future agronomic applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Genetic improvement of sesame by induced mutations

    International Nuclear Information System (INIS)

    1988-01-01

    Full text: This project started in 1983 with assistance by IAEA at the Agricultural Department of Zulia University and with co-operation of FONALI. The main objective was the development of mutants with early ripening, between 85 and 95 days, which are drought and disease resistant. During experimentation in Portuguesa and Oriente, with materials produced under this project researchers identified about 20 mutants that show promise in terms of high yield, earliness and disease resistance. Among them are two mutants of the Piritu variety, P-10-7412 (early), and P-10-7412 (medium); four mutants of Criollo Falcon, CF 6-N3H494, CF 53-8874, CF 35-9306 and CF 25-9382, and a Venezuela 44 mutant, III-8408. They exhibit early flowering at 35-45 days, are resistant to the problematic leaf diseases (Cylindrosporium and Cercospora, are resistant to Macrophomina, are drought tolerant and possibly also virus resistant. These new potential varieties coincide in ripening time, have a good appearance, and show little or no branching, good root development and a good average yield of at least 1000 kg/ha, with a potential of 1500-2000 kg/ha. (author)

  18. Genetic improvement of sesame by induced mutations

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1988-07-01

    Full text: This project started in 1983 with assistance by IAEA at the Agricultural Department of Zulia University and with co-operation of FONALI. The main objective was the development of mutants with early ripening, between 85 and 95 days, which are drought and disease resistant. During experimentation in Portuguesa and Oriente, with materials produced under this project researchers identified about 20 mutants that show promise in terms of high yield, earliness and disease resistance. Among them are two mutants of the Piritu variety, P-10-7412 (early), and P-10-7412 (medium); four mutants of Criollo Falcon, CF 6-N3H494, CF 53-8874, CF 35-9306 and CF 25-9382, and a Venezuela 44 mutant, III-8408. They exhibit early flowering at 35-45 days, are resistant to the problematic leaf diseases Cylindrosporium and Cercospora, are resistant to Macrophomina, are drought tolerant and possibly also virus resistant. These new potential varieties coincide in ripening time, have a good appearance, and show little or no branching, good root development and a good average yield of at least 1000 kg/ha, with a potential of 1500-2000 kg/ha. (author)

  19. QUALIDADE FISIOLÓGICA E SANITÁRIA DE SEMENTES DE MELÃO UTILIZADAS NO PÓLO AGRÍCOLA ASSU-BARAÚNA-MOSSORÓ

    Directory of Open Access Journals (Sweden)

    Andreya Kalyana de Oliveira

    2008-01-01

    Full Text Available This research was conducted to evaluate the physiological and sanity quality of melon (Cucumis melo L. seeds used in agricultural region Assu-Baraúna-Mosssó in the Rio Grande do Norte. For seed lots each from the hybrids Goldex and Vereda were used. Research was conducted at the Seed Analysis Laboratory and Irrigation Agricultural of the Department of Crop Science of the UFERSA from August 2006 to July 2007. The physiological quality was evaluated by the germination, first count germination, accelerated aging, emergence speed index, electrical conductivity and seedling emergence, beyond the seed moisture content. The sanity was determinated by the method of filter paper with freezer, in four replications with 100 seeds per lot and completly randomized design. From the results obtained, it was concluded that first count germination, accelerated aging, electrical conductivity and seedling emergence tests only identified low and high seed lot from the hybrids Goldex and Vereda. The electrical conductivity test is most indicated to estimation of melon seed physiological potential, it was also possible to reduce the imbibition period of seeds prior this test. The pathogens associated with melon seeds were Aspergillus spp., Fusarium sp. and Macrophomina sp. and the physiological quality of seeds was not affected with the microrganisms presence.

  20. Some Orchid Species Fungi Isolated by Different Methods

    Directory of Open Access Journals (Sweden)

    Arzu ÇIĞ

    2014-03-01

    Full Text Available Due to their very small seeds that do not contain endosperm, many terrestrial orchid species require the presence of fungi in order to germinate and maintain their lives; and symbiotic culture studies are being carried out on this topic. For the purpose of determining the orchid species on which the fungus to be used as inoculants in the symbiotic culture will be effective, fungi isolated through several isolation methods are cultured with orchid species. In this study a total of four different isolation methods were applied as one on the tubers and rhizomes and three on the soil of eleven orchid species from the Anacamptis, Cephalanthera, Dactylorhiza and Orchis genera. Three different culture media were used in the methods. At the end of the study Alternaria, Aspergillus, Fusarium, Macrophomina, Rhizoctonia, Trichoderma and Verticillium fungi were isolated. In the study that was conducted with the aimed to isolate particularly Rhizoctania spp. fungi, the fungi was isolated from the tubers of Dactylorhiza umbrosa and Orchis palustris species and the soil of the Orchis simia species. Fusarium and Aspergillus species were isolated the most in all implemented methods and from all species.

  1. Antifungical Activity of Autochthonous Bacillus subtilis Isolated from Prosopis juliflora against Phytopathogenic Fungi.

    Science.gov (United States)

    Abdelmoteleb, Ali; Troncoso-Rojas, Rosalba; Gonzalez-Soto, Tania; González-Mendoza, Daniel

    2017-12-01

    The ability of Bacillus subtilis , strain ALICA to produce three mycolytic enzymes (chitinase, β-1,3-glucanase, and protease), was carried out by the chemical standard methods. Bacillus subtilis ALICA was screened based on their antifungal activity in dual plate assay and cell-free culture filtrate (25%) against five different phytopathogenic fungi Alternaria alternata , Macrophomina sp., Colletotrichum gloeosporioides , Botrytis cinerea , and Sclerotium rolfesii . The B. subtilis ALICA detected positive for chitinase, β-1,3-glucanase and protease enzymes. Fungal growth inhibition by both strain ALICA and its cell-free culture filtrate ranged from 51.36% to 86.3% and 38.43% to 68.6%, respectively. Moreover, hyphal morphological changes like damage, broken, swelling, distortions abnormal morphology were observed. Genes expression of protease, β-1,3-glucanase, and lipopeptides (subtilosin and subtilisin) were confirmed their presence in the supernatant of strain ALICA. Our findings indicated that strain ALICA provided a broad spectrum of antifungal activities against various phytopathogenic fungi and may be a potential effective alternative to chemical fungicides.

  2. Adaptive introductions: How multiple experiments and comparisons to wild populations provide insights into requirements for long-term introduction success of an endangered shrub

    Institute of Scientific and Technical Information of China (English)

    Eric S.Menges; Stacy A.Smith; Carl W.Weekley

    2016-01-01

    Recovery of an imperiled plant species may require augmentation of existing populations or creation of new ones.Hundreds of such projects have been conducted over the last few decades,but there is a bias in the literature favoring successes over failures.In this paper,we evaluate a series of introductions that experimentally manipulated microhabitat and fire in an adaptive introduction framework.Between 2002 and 2012,we (and our collaborators) carried out ten introductions and augmentations of Florida ziziphus Pseudoziziphus (Condalia,Ziziphus) celata,a clonal shrub limited to very small populations and narrowly endemic to pyrogenic central Florida sandhills.Six of the introductions were designed as experiments to test hypotheses about how demographic performance was affected by microhabitat,fire,and propagule type.Introduced transplants had high survival (<90% annually),inconsistent growth,and little transition to reproduction,while introduced seeds had low germination and survival.Transplants were more efficient than seeds as translocation propagules.Shaded (vs.open) sites supported generally higher transplant and seedling survival and seed germination percentages,but growth responses varied among experiments.Supplemental irrigation increased transplant survival and seed germination,but otherwise seedling and plant survival and growth were not significantly affected.Contrary to expectations based on wild populations,introduced propagules have not been more successful in unshaded sites,suggesting that Florida ziziphus has broader microhabitat preferences than hypothesized.Compared to wild plants,introduced plants had similar survival and responses to fire,slower growth,and more delayed flowering.Introduced plants had no clonal spread.While no introduced population has demonstrated a capacity for long-term viability,one augmented population has flowered and produced viable fruits.Given that Florida ziziphus genets are long-lived,low levels of sexual

  3. Gravity regulation in tuber-bearing moss Leptobryum pyriforme (Hedw.) Wilson

    Science.gov (United States)

    Lobachevska, Oksana

    Considerable number of moss species is propagated asexually, and asexual reproduction is the key factor of their life strategy and effective mechanism of rapid population and attaching plants to habitats with great environmental fluctuations (Velde et al., 2001; Frey, Kűrshner, 2010). It has been shown for the first time for gravisensitive species Leptobryum pyriforme (Hedw.) Wilson that the development of propagules as organs of vegetative reproduction and accumulation of nutrient substances is gravidependent phenomenon. L. pyriforme differs from other moss species in higher growth and development rate. In darkness the greatest bundle of gravisensitive negatively gravitropic filaments (above 50 filaments) of both caulonemal and chloronemal type arised from 1 protonemal ball of moss. Perhaps, it is caused by high protonema gravisensitivity and morphogenetic effectiveness of gravitation force. It has been shown that propagules of L. pyriforme are formed much faster in darkness and their number is twice higher than on light. After five-day clinorotation of the L. pyriforme turfs the number of propagules is lower in darkness compared to gravistimulated turfs and higher than on the light. Thus, vegetative reproduction of L. pyriforme is the gravidependent process and gravitation force has stimulating influence on the formation of propagula. In L. pyriforme rhizoid tubers from round to oval (93-116 x ({) } (x) 120-148 muμm) are formed from 5-6 big cells (70 x ({) } (x) 80 muμm). Due to small capsules, L{it pyriforme }does not have a lot of big spores which are spread to insignificant distances, the mass formation of brood organs promotes moss survival and its preservation. The results of investigation prove the participation of rhizoids and rhizoid tubers as imperceptible but important phase of vital cycle of moss species - settlers in realization of vital tolerance strategy to extreme conditions of temporarily available habitats: due to rapid method of spatial

  4. CONTRIBUTIONS OF SEXUAL AND ASEXUAL REPRODUCTION TO POPULATION STRUCTURE IN THE CLONAL SOFT CORAL, ALCYONIUM RUDYI.

    Science.gov (United States)

    McFadden, Catherine S

    1997-02-01

    Numerous studies of population structure in sessile clonal marine invertebrates have demonstrated low genotypic diversity and nonequilibrium genotype frequencies within local populations that are monopolized by relatively few, highly replicated genets. All of the species studied to date produce planktonic sexual propagules capable of dispersing long distances; despite local genotypic disequilibria, populations are often panmictic over large geographic areas. The population structure paradigm these species represent may not be typical of the majority of clonal invertebrate groups, however, which are believed to produce highly philopatric sexual propagules. I used allozyme variation to examine the population structure of the temperate soft coral, Alcyonium rudyi, a typical clonal species whose sexually produced larvae and asexually produced ramets both have very low dispersal capabilities. Like other clonal plants and invertebrates, the local population dynamics of A. rudyi are dominated by asexual reproduction, and recruitment of new sexually produced genets occurs infrequently. As expected from its philopatric larval stage, estimates of genetic differentiation among populations of A. rudyi were highly significant at all spatial scales examined (mean θ = 0.300 among 20 populations spanning a 1100-km range), suggesting that genetic exchange seldom occurs among populations separated by as little as a few hundred meters. Mapping of multilocus allozyme genotypes within a dense aggregation of A. rudyi ramets confirmed that dispersal of asexual propagules is also very limited: members of the same genet usually remain within invertebrates, populations of A. rudyi do not appear to be dominated by a few widespread genets: estimates of genotypic diversity (G o ) within 20 geographically distinct populations did not differ from expectations for outcrossing, sexual populations. Despite theoretical suggestions that philopatric dispersal combined with typically small effective

  5. Capacidade infectiva de fungos micorrízicos arbusculares em áreas reflorestadas após mineração de bauxita no Pará Infective capacity of arbuscular mycorrhizal fungi in reforested areas after bauxite mining in the Pará State, Brazil

    Directory of Open Access Journals (Sweden)

    Ana Lucy Caproni

    2003-08-01

    Full Text Available O objetivo deste trabalho foi avaliar a capacidade infectiva das espécies de fungos micorrízicos arbusculares (FMA e relacionála com o número mais provável (NMP de propágulos infectivos e número de esporos extraídos diretamente do campo. Amostras de solo foram coletadas em áreas degradadas pela mineração de bauxita com cobertura de 2, 6, 12 e 16 anos após revegetação e em uma área de floresta primária, em Porto Trombetas, PA. Os esporos de FMA foram extraídos e identificados taxonomicamente por suas características morfológicas. A maioria das espécies apresentou comportamento diferente nas áreas em estudo. Glomus macrocarpum foi a que apresentou infectividade mais rápida e alto potencial infectivo, nos solos das cinco áreas estudadas. Esta espécie também apresentou alto NMP de propágulos e alto número de esporos em todas as áreas estudadas. A capacidade infectiva das espécies não está relacionada com a densidade de propágulos. As espécies de FMA possuem diferentes graus de tolerância às condições de solo e se comportaram de maneira diferente de acordo com a idade da revegetação.The objective of this work was to evaluate the infective capacity of arbuscular mycorrhizal fungi (AMF species and relate it to the most probable number (MPN of infective propagules and number of spores extracted directly from the field. Soil samples were taken from areas degraded by bauxite mining, 2, 6, 12 and 16 years after reforestation and from an area of primary forest. The spores were extracted and morphologically identified. Most of the species had different behavior for the areas of study. Glomus macrocarpum showed fast infectivity in soils with high infective potential, independently of the soil origin. This species also showed high MPN values of infective propagules and high number of spores in all areas. The infective capacity of the species did not relate to the density of infective propagules. AMF species have different

  6. Urbanized landscapes favored by fig-eating birds increase invasive but not native juvenile strangler fig abundance.

    Science.gov (United States)

    Caughlin, Trevor; Wheeler, Jessica H; Jankowski, Jill; Lichstein, Jeremy W

    2012-07-01

    Propagule pressure can determine the success or failure of invasive plant range expansion. Range expansion takes place at large spatial scales, often encompassing many types of land cover, yet the effect of landscape context on propagule pressure remains largely unknown. Many studies have reported a positive correlation between invasive plant abundance and human land use; increased propagule pressure in these landscapes may be responsible for this correlation. We tested the hypothesis that increased rates of seed dispersal by fig-eating birds, which are more common in urban habitats, result in an increase in invasive strangler fig abundance in landscapes dominated by human land use. We quantified abundance of an invasive species (Ficus microcarpa) and a native species (F. aurea) of strangler fig in plots spanning the entire range of human land use in South Florida, USA, from urban parking lots to native forest. We then compared models that predicted juvenile fig abundance based on distance to adult fig seed sources and fig-eating bird habitat quality with models that lacked one or both of these terms. The best model for juvenile invasive fig abundance included both distance to adult and fig-eating bird habitat terms, suggesting that landscape effects on invasive fig abundance are mediated by seed-dispersing birds. In contrast, the best model for juvenile native fig abundance included only presence/absence of adults, suggesting that distance from individual adult trees may have less effect on seed limitation for a native species compared to an invasive species undergoing range expansion. However, models for both species included significant effects of adult seed sources, implying that juvenile abundance is limited by seed arrival. This result was corroborated by a seed addition experiment that indicated that both native and invasive strangler figs were strongly seed limited. Understanding how landscape context affects the mechanisms of plant invasion may lead to

  7. Large-scale ocean connectivity and planktonic body size

    KAUST Repository

    Villarino, Ernesto

    2018-01-04

    Global patterns of planktonic diversity are mainly determined by the dispersal of propagules with ocean currents. However, the role that abundance and body size play in determining spatial patterns of diversity remains unclear. Here we analyse spatial community structure - β-diversity - for several planktonic and nektonic organisms from prokaryotes to small mesopelagic fishes collected during the Malaspina 2010 Expedition. β-diversity was compared to surface ocean transit times derived from a global circulation model, revealing a significant negative relationship that is stronger than environmental differences. Estimated dispersal scales for different groups show a negative correlation with body size, where less abundant large-bodied communities have significantly shorter dispersal scales and larger species spatial turnover rates than more abundant small-bodied plankton. Our results confirm that the dispersal scale of planktonic and micro-nektonic organisms is determined by local abundance, which scales with body size, ultimately setting global spatial patterns of diversity.

  8. Utilization of emergent aquatic plants for biomass-energy-systems development

    Energy Technology Data Exchange (ETDEWEB)

    Kresovich, S.; Wagner, C.K.; Scantland, D.A.; Groet, S.S.; Lawhon, W.T.

    1982-02-01

    A review was conducted of the available literature pertaining to the following aspects of emergent aquatic biomass: identification of prospective emergent plant species for management; evaluation of prospects for genetic manipulation; evaluation of biological and environmental tolerances; examination of current production technologies; determination of availability of seeds and/or other propagules, and projections for probable end-uses and products. Species identified as potential candidates for production in biomass systems include Arundo donax, Cyperus papyrus, Phragmites communis, Saccharum spontaneum, Spartina alterniflora, and Typha latifolia. If these species are to be viable candidates in biomass systems, a number of research areas must be further investigated. Points such as development of baseline yield data for managed systems, harvesting conceptualization, genetic (crop) improvement, and identification of secondary plant products require refinement. However, the potential pay-off for developing emergent aquatic systems will be significant if development is successful.

  9. Toxic micromycetes in grain raw material during its processing.

    Science.gov (United States)

    Lugauskas, Albinas; Raila, Algirdas; Railiene, Marija; Raudoniene, Vita

    2006-01-01

    In 2003-2005 micromycetes were isolated and identified from wheat, barley, rye, buckwheat grain brought into mills or from processing enterprises. Contamination of the produced flour with micromycete propagules (cfu g(-1)), changes in micromycete diversity and abundance in the course of flour storage, preparation and baking of bread, production of groats or other food products and fodder were determined. Most attention was given to widely distributed micromycetes, known producers of toxins: Alternaria alternata, Aspergillus candidus, A. clavatus, A. flavus, A. fumigatus, A. niger, A. oryzae, A. (=Eurotium) repens, Fusarium culmorum, F. equiseti, F. graminearum, F. moniliforme, F. oxysporum, F. poae, F. sporotrichioides, Penicillium brevicompactum, P. chrysogenum, P. cyclopium, P. daleae, P. expansum, P. funiculosum, P. roqueforti, P. urticae, P. verruculosum, P. viridicatum, Phoma exiqua, Rhizomucor pusillus, Rhizopus stolonifer, Trichothecium roseum. Abilities of these micromycetes to produce secondary toxic metabolites were determined as well as possible hazard caused to people consuming the contaminated products.

  10. Maternal programming of defensive responses through sustained effects on gene expression.

    Science.gov (United States)

    Zhang, Tie-Yuan; Bagot, Rose; Parent, Carine; Nesbitt, Cathy; Bredy, Timothy W; Caldji, Christian; Fish, Eric; Anisman, Hymie; Szyf, Moshe; Meaney, Michael J

    2006-07-01

    There are profound maternal effects on individual differences in defensive responses and reproductive strategies in species ranging literally from plants to insects to birds. Maternal effects commonly reflect the quality of the environment and are most likely mediated by the quality of the maternal provision (egg, propagule, etc.), which in turn determines growth rates and adult phenotype. In this paper we review data from the rat that suggest comparable forms of maternal effects on defensive responses stress, which are mediated by the effects of variations in maternal behavior on gene expression. Under conditions of environmental adversity maternal effects enhance the capacity for defensive responses in the offspring. In mammals, these effects appear to 'program' emotional, cognitive and endocrine systems towards increased sensitivity to adversity. In environments with an increased level of adversity, such effects can be considered adaptive, enhancing the probability of offspring survival to sexual maturity; the cost is that of an increased risk for multiple forms of pathology in later life.

  11. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    Science.gov (United States)

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-01-01

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services. PMID:25005713

  12. The effect of carbon supply on allocation to allelochemicals and caterpillar consumption of peppermint.

    Science.gov (United States)

    Lincoln, D E; Couvet, D

    1989-01-01

    The carbon supply of peppermint plants was manipulated by growing clonal propagules under three carbon dioxide regimes (350, 500 and 650 μl l -1 ). Feeding by fourth instar caterpillars of Spodoptera eridania increased with elevated CO 2 hostplant regime, as well as with low leaf nitrogen content and by a high proportion of leaf volatile terpenoids. Leaf weight increased significantly with the increased carbon supply, but the amount of nitrogen per leaf did not change. The amount of volatile leaf mono-and sesquiterpenes increased proportionately with total leaf dry weight and hence was not influenced by CO 2 supply. These results are consistent with ecological hypotheses which assume that allocation to defense is closely regulated and not sensitive to carbon supply per se.

  13. The worldwide expansion of the Argentine ant

    DEFF Research Database (Denmark)

    Vogel, Valerie; Pedersen, Jes Søe; Giraud, Tatiana

    2010-01-01

    Aim The aim of this study was to determine the number of successful establishments of the invasive Argentine ant outside native range and to see whether introduced supercolonies have resulted from single or multiple introductions. We also compared the genetic diversity of native versus introduced...... supercolonies to assess the size of the propagules (i.e. the number of founding individuals) at the origin of the introduced supercolonies. Location Global. Methods We used mitochondrial DNA (mtDNA) markers and microsatellite loci to study 39 supercolonies of the Argentine ant Linepithema humile covering both......) and secondary introductions (from sites with established invasive supercolonies) were important in the global expansion of the Argentine ant. In combination with the similar social organization of colonies in the native and introduced range, this indicates that invasiveness did not evolve recently as a unique...

  14. Características anatômicas de mudas de morangueiro micropropagadas com diferentes fontes de silício Anatomical characteristics of the strawberry seedlings micropropagated using different sources of silicon

    Directory of Open Access Journals (Sweden)

    Francyane Tavares Braga

    2009-02-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito de diferentes fontes de silício, utilizadas na micropropagação, nas características anatômicas de mudas de morangueiro (Fragaria x ananassa. Foram utilizados propágulos da cv. Oso Grande cultivados em meio Murashige e Skoog (MS, acrescido de 30 gL-1 de sacarose, 6 gL-1 de ágar e 1 mgL-1 de 6-benzilaminopurina. Os tratamentos consistiram da adição ao meio MS dos silicatos de cálcio, de sódio e de potássio, na dosagem de 1 gL-1. O tratamento testemunha foi o meio MS sem fonte de silício. Odelineamento experimental foi o inteiramente ao acaso, com dez repetições. Os propágulos foram mantidos por 45 dias em sala de crescimento, em condições controladas. Avaliaram-se características fitotécnicas e anatômicas dos propágulos in vitro. Verificou-se que o aumento da massa de matéria fresca e seca dos propágulos de morangueiro ocorreu na presença de silicato de sódio. Asuplementação do meio de cultura com silício proporcionou maior teor de clorofila. Aadição de silicato de sódio ao meio MS resultou em aumento da espessura dos tecidos do limbo foliar e da deposição de cera epicuticular e na formação de depósito de silício nas células.The objective of this work was to evaluate the effect of different silicon sources, used in micropropagation, on the anatomical characteristics of strawberry's (Fragaria x ananassa seedlings. Propagules of cv.Oso Grande were cultivated on a Murashige and Skoog (MS medium containing 30 gL-1 of sucrose, 6 gL-1 of agar and 1mgL-1 of 6-benzylamino purine. The treatments consisted of calcium, sodium, or potassium silicates added to the MS medium, at the dosage of 1 gL-1. The MS medium without added silicon was the check treatment. The experimental design was completely randomized with ten replications. The propagules were maintained during 45days in a growth chamber, under controlled conditions. Developmental and anatomical characteristics of the

  15. Mortality risk from entomopathogenic fungi affects oviposition behavior in the parasitoid wasp Trybliographa rapae

    DEFF Research Database (Denmark)

    Rännbäck, Linda-Marie; Cotes, Belen; Anderson, Peter

    2015-01-01

    brunneum isolate KVL 04-57 and Beauveria bassiana isolate KVL 03-90. Furthermore, T. rapae oviposition behavior was assessed in the presence of these entomopathogenic fungi either as infected hosts or as infective propagules in the environment. Both fungi were pathogenic to D. radicum larvae and T. rapae...... adults, but with variable virulence. When host patches were inoculated with M. brunneum conidia in a no-choice situation, more eggs were laid by T. rapae in hosts of those patches compared to control and B. bassiana treated patches. Females that later succumbed to mycosis from either fungusi laid...... larvae. This was less pronounced for B. bassiana. Based on our results we propose that T. rapae can perceive and react towards IGP risk posed by M. brunneum but not B. bassiana to the foraging female herself and her offspring. Thus, M. brunneum has the potential to be used for biological control against...

  16. Aerobiology Over Antarctica - A New Initiative for Atmospheric Ecology.

    Science.gov (United States)

    Pearce, David A; Alekhina, Irina A; Terauds, Aleks; Wilmotte, Annick; Quesada, Antonio; Edwards, Arwyn; Dommergue, Aurelien; Sattler, Birgit; Adams, Byron J; Magalhães, Catarina; Chu, Wan-Loy; Lau, Maggie C Y; Cary, Craig; Smith, David J; Wall, Diana H; Eguren, Gabriela; Matcher, Gwynneth; Bradley, James A; de Vera, Jean-Pierre; Elster, Josef; Hughes, Kevin A; Cuthbertson, Lewis; Benning, Liane G; Gunde-Cimerman, Nina; Convey, Peter; Hong, Soon Gyu; Pointing, Steve B; Pellizari, Vivian H; Vincent, Warwick F

    2016-01-01

    The role of aerial dispersal in shaping patterns of biodiversity remains poorly understood, mainly due to a lack of coordinated efforts in gathering data at appropriate temporal and spatial scales. It has been long known that the rate of dispersal to an ecosystem can significantly influence ecosystem dynamics, and that aerial transport has been identified as an important source of biological input to remote locations. With the considerable effort devoted in recent decades to understanding atmospheric circulation in the south-polar region, a unique opportunity has emerged to investigate the atmospheric ecology of Antarctica, from regional to continental scales. This concept note identifies key questions in Antarctic microbial biogeography and the need for standardized sampling and analysis protocols to address such questions. A consortium of polar aerobiologists is established to bring together researchers with a common interest in the airborne dispersion of microbes and other propagules in the Antarctic, with opportunities for comparative studies in the Arctic.

  17. SPATIAL ANALYSIS FRAMEWORK FOR MANGROVE FORESTS RESTORATION

    Directory of Open Access Journals (Sweden)

    Arimatéa de Carvalho Ximenes

    2016-09-01

    Full Text Available Mangroves are coastal ecosystems in transition between sea and land, localized worldwide on the tropical and subtropical regions. However, anthropogenic pressure in coastal areas has led to the conversion of many mangrove areas to other uses. Due to the increased awareness of the importance of mangroves worldwide, restoration methods are being studied. Our aim is to develop a framework for selecting suitable sites for red mangrove planting using Geographic Information Systems (GIS. For this reason, the methodology is based on abiotic factors that have an influence on the zonation (distribution and growing of the Rhizophora mangle. A total suitable area of 6,12 hectares was found, where 15.300 propagules could be planted.

  18. Arbuscular mycorrhizal fungi in a semi-arid, limestone mining-impacted area of Brazil

    Directory of Open Access Journals (Sweden)

    Thaís Teixeira-Rios

    2013-12-01

    Full Text Available The main goal of this study was to determine the diversity and activity of arbuscular mycorrhizal fungi (AMF in an area degraded by limestone mining within the semi-arid region of Brazil known as the caatinga (shrublands. Near a limestone quarry, we selected two areas of caatinga (preserved and degraded for study. The number of glomerospores did not differ significantly between the two areas. There was a trend toward the most probable number of infective propagules being higher in the degraded area. Twenty AMF taxa were identified in the two sampled areas, species richness, diversity and evenness being higher in the preserved area. Two species of Racocetra represent new records for the semi-arid region of Brazil. Glomerospore production and AMF species richness were unaffected by mining activity in the study area.

  19. Fusarium oxysporum and the Fusarium Wilt Syndrome.

    Science.gov (United States)

    Gordon, Thomas R

    2017-08-04

    The Fusarium oxysporum species complex (FOSC) comprises a multitude of strains that cause vascular wilt diseases of economically important crops throughout the world. Although sexual reproduction is unknown in the FOSC, horizontal gene transfer may contribute to the observed diversity in pathogenic strains. Development of disease in a susceptible crop requires F. oxysporum to advance through a series of transitions, beginning with spore germination and culminating with establishment of a systemic infection. In principle, each transition presents an opportunity to influence the risk of disease. This includes modifications of the microbial community in soil, which can affect the ability of pathogen propagules to survive, germinate, and infect plant roots. In addition, many host attributes, including the composition of root exudates, the structure of the root cortex, and the capacity to recognize and respond quickly to invasive growth of a pathogen, can impede development of F. oxysporum.

  20. The evolution of sociality in spiders

    DEFF Research Database (Denmark)

    Lubin, Yael; Bilde, T.

    2007-01-01

    . Anelosimus (Theridiidae) C. Sociality in Spiders: An Evolutionary Dead End? V. Evolution and Maintenance of Sociality in Spiders: Relevant Models A. Kin Selection 1. Kin Recognition 2. Inbreeding and Kin Selection B. Multilevel Selection (Group Selection) C. Ecological Benefits D. Ecological Constraints E......I. Introducing Social Spiders II. Social and Subsocial Species: A Survey of Behavioral Traits III. Inbred Sociality in Spiders A. Cooperation Versus Competition: A Balancing Act B. Do Social Spiders Have Division of Labor? C. Colony Foundation: Propagule Dispersal Versus Fission D. Female......-Biased Colony Sex Ratios: Primary and Operational Sex Ratios E. Mating System: Inbreeding and Its Population-Genetic Consequences F. "Boom and Bust" Colony Dynamics IV. Phylogenetic Relationships Among Social Spider Species A. Common Features of Social Evolution B. Case Studies 1. Stegodyphus (Eresidae) 2...

  1. Large-scale ocean connectivity and planktonic body size

    KAUST Repository

    Villarino, Ernesto; Watson, James R.; Jö nsson, Bror; Gasol, Josep M.; Salazar, Guillem; Acinas, Silvia G.; Estrada, Marta; Massana, Ramó n; Logares, Ramiro; Giner, Caterina R.; Pernice, Massimo C.; Olivar, M. Pilar; Citores, Leire; Corell, Jon; Rodrí guez-Ezpeleta, Naiara; Acuñ a, José Luis; Molina-Ramí rez, Axayacatl; Gonzá lez-Gordillo, J. Ignacio; Có zar, André s; Martí , Elisa; Cuesta, José A.; Agusti, Susana; Fraile-Nuez, Eugenio; Duarte, Carlos M.; Irigoien, Xabier; Chust, Guillem

    2018-01-01

    Global patterns of planktonic diversity are mainly determined by the dispersal of propagules with ocean currents. However, the role that abundance and body size play in determining spatial patterns of diversity remains unclear. Here we analyse spatial community structure - β-diversity - for several planktonic and nektonic organisms from prokaryotes to small mesopelagic fishes collected during the Malaspina 2010 Expedition. β-diversity was compared to surface ocean transit times derived from a global circulation model, revealing a significant negative relationship that is stronger than environmental differences. Estimated dispersal scales for different groups show a negative correlation with body size, where less abundant large-bodied communities have significantly shorter dispersal scales and larger species spatial turnover rates than more abundant small-bodied plankton. Our results confirm that the dispersal scale of planktonic and micro-nektonic organisms is determined by local abundance, which scales with body size, ultimately setting global spatial patterns of diversity.

  2. Biological invasions in the Antarctic: extent, impacts and implications.

    Science.gov (United States)

    Frenot, Yves; Chown, Steven L; Whinam, Jennie; Selkirk, Patricia M; Convey, Peter; Skotnicki, Mary; Bergstrom, Dana M

    2005-02-01

    Alien microbes, fungi, plants and animals occur on most of the sub-Antarctic islands and some parts of the Antarctic continent. These have arrived over approximately the last two centuries, coincident with human activity in the region. Introduction routes have varied, but are largely associated with movement of people and cargo in connection with industrial, national scientific program and tourist operations. The large majority of aliens are European in origin. They have both direct and indirect impacts on the functioning of species-poor Antarctic ecosystems, in particular including substantial loss of local biodiversity and changes to ecosystem processes. With rapid climate change occurring in some parts of Antarctica, elevated numbers of introductions and enhanced success of colonization by aliens are likely, with consequent increases in impacts on ecosystems. Mitigation measures that will substantially reduce the risk of introductions to Antarctica and the sub-Antarctic must focus on reducing propagule loads on humans, and their food, cargo, and transport vessels.

  3. Characterization of Italian isolates of Inonotus rickii

    Directory of Open Access Journals (Sweden)

    Tiziana ANNESI

    2011-01-01

    Full Text Available Thirty-seven isolates of Inonotus rickii, a pathogenic fungus causing white rot and cankers, were collected from diseased boxelder trees lining boulevards in Rome and from other hosts in Rome and Sicily. During the survey, it was observed that this fungus occasionally produced basidiomes, but more frequently it had anamorphic structures that released a brown powdery mass of chlamydospores, presumably acting as asexual propagules. All isolates were characterized using random amplified microsatellite analysis and somatic incompatibility tests in order to investigate the diversity of genotypes within and between the different disease centers surveyed in Italy. The results suggest that both sexual and asexual reproduction play an important role in the spread of this disease, with important epidemiological implications. .

  4. Spatiotemporal trends in Canadian domestic wild boar production and habitat predict wild pig distribution

    DEFF Research Database (Denmark)

    Michel, Nicole; Laforge, Michel; van Beest, Floris

    2017-01-01

    eradication of wild pigs is rarely feasible after establishment over large areas, effective management will depend on strengthening regulations and enforcement of containment practices for Canadian domestic wild boar farms. Initiation of coordinated provincial and federal efforts to implement population...... wild boar and test the propagule pressure hypothesis to improve predictive ability of an existing habitat-based model of wild pigs. We reviewed spatiotemporal patterns in domestic wild boar production across ten Canadian provinces during 1991–2011 and evaluated the ability of wild boar farm...... distribution to improve predictive models of wild pig occurrence using a resource selection probability function for wild pigs in Saskatchewan. Domestic wild boar production in Canada increased from 1991 to 2001 followed by sharp declines in all provinces. The distribution of domestic wild boar farms in 2006...

  5. Axenic culture and encapsulation of the intraradical forms of Glomus spp.

    Science.gov (United States)

    Strullu, D G; Romand, C; Plenchette, C

    1991-05-01

    In recent years there have been many attempts to cultivate in vitro vesicular-arbuscular mycorrhizal (VAM) fungi which are obligate symbionts. Resting spores extracted from soils are often used as inoculum. Mycorrhizal root pieces are also used for inoculation but the role of intra-radical structures has not been clearly established. On agar medium vegetative mycelium was regenerated from individual intra-radical vesicles and from hyphae extracted by enzymatic maceration. After cell penetration, the mycelium probably accumulates substances which allow growth of VAM fungi in pure culture. When associated with tomato roots, this mycelium forms typical mycorrhizae. Encapsulation stabilized the biological properties of mycorrhizal roots and isolated vesicles. The immobilization also preserved the infectivity of the intra-radical hyphae and vesicles. After 25 years of exclusive utilization of resting spores as starting material for axenic and dual cultures of VAM fungi, it appears that intra-radical vesicles may be preferable propagules.

  6. VAM populations in relation to grass invasion associated with forest decline.

    Science.gov (United States)

    Vosatka, M; Cudlin, P; Mejstrik, V

    1991-01-01

    Spruce stands in Northern Bohemia forests, damaged to various degrees by industrial pollution, have shown establishment of grass cover following tree defoliation. Populations of vesicular-arbuscular mycorrhizal (VAM) fungi were studied under this grass cover in four permanent plots with spruce under different levels of pollution stress. Soil and root samples were collected in April and June within each plot as follows: (1) sites without grass, (2) sites with initial stages of grass invasion, and (3) sites with fully developed grass cover. In all plots, the highest number of propagules were recovered from samples taken from sites having full grass cover. Mycorrhizal infection of grass was highest in the plot with the severest pollution damage and lowest in the least damaged plot. The development of grass cover and VAM infection of grass increased with tree defoliation caused by air pollution.

  7. The role of mycorrhizal fungi and microsites in primary succession on Mount St. Helens.

    Science.gov (United States)

    Titus, J; Del Moral, R

    1998-03-01

    This study was designed to examine the role of vesicular-arbuscular mycorrhizae (VAM) and microsites on the growth of pioneer species. Flat, rill, near-rock, and dead lupine microsites were created in plots in barren areas of the Pumice Plain of Mount St. Helens. VAM propagules were added to the soil in half of the plots. Six pioneer species were planted into both VAM and non-VAM inoculated microsites. Plants in dead lupine microsites were greater in biomass than those in flat, rill, and near-rock microsites. Significant effects of VAM on plant biomass did not occur. Microsites continue to be important to plant colonization on the Pumice Plain, but VAM do not yet appear to play an important role. This may be due to limited nutrient availability and the facultatively mycotrophic nature of the colonizing plant species. It is unlikely that VAM play an important role in successional processes in newly emplaced nutrient-poor surfaces.

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

    DEFF Research Database (Denmark)

    Christensen, H.; Jakobsen, I.

    1993-01-01

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

  9. Fungi in neotropical epiphyte roots.

    Science.gov (United States)

    Bermudes, D; Benzing, D H

    1989-01-01

    Roots of thirty-eight Ecuadoran vascular epiphytes, representing eleven angiosperm families, were examined for the presence of symbiotic microorganisms. Most orchid roots contained fungal endophytes like those that regularly infect terrestrial counterparts. Hyphae were also common in and on nonorchid roots, but assignments of these relationships to known mycorrhizal morphologies was not possible in all cases. Evidence of vesicular-arbuscular mycorrhizae (VAM) existed in a number of subjects while in Ericaceae and Campanulaceae a fungal association similar to the demateaceous surface fungi (DSF) described for alpine and prarie plants was usually present. Some associations were characterized by multicellular propagules on root surfaces. The significance of these findings and the factors likely to influence occurrence and consequences of root-fungus mutualisms in tropical forest canopies are discussed. Facts and considerations that could aid future inquiry on these systems are provided.

  10. The fast expansion of Pyropia aquaculture in ;Sansha; regions should be mainly responsible for the Ulva blooms in Yellow Sea

    Science.gov (United States)

    Zhang, Jianheng; Zhao, Peng; Huo, Yuanzi; Yu, Kefeng; He, Peimin

    2017-04-01

    Massive Ulva blooms became an environmental disaster in the Yellow Sea from 2007 to 2015. In this study, field shipboard observations indicated that Ulva blooms originated in Pyropia aquaculture area, and the morphology of initial floating Ulva seaweed have the structure of rhizoid, which is similar with the attached Ulva on the Pyropia rafts. The spatial distribution of Ulva microscopic propagules in the southern Yellow Sea also supported that the blooms originated in the Pyropia aquaculture area. Besides, numerical model was used in this study, showing the origin of macroalgal blooms was traced to "Sansha" regions which accounted for almost 70% of the total Pyropia aquaculture area. We conclude that the significant biomass (4252 tons) of Ulva species on the Pyropia rafts during the harvesting season in "Sansha" regions played an important role in the early rapid development of blooms in the Yellow Sea.

  11. Climate Change Influences on Species Interrelationships and Distributions in High-Arctic Greenland

    DEFF Research Database (Denmark)

    D. R., Klein; Bruun, H. H.; Lundgren, R.

    2008-01-01

    , reproduction, and dispersal of all life forms present. Climate-associated changes in the biotic communities of the region are altering inter-species interactions, notably pollination, seed dispersal and plant-herbivore relations. Sexual reproduction and dispersal of propagules, primarily seeds, are essential...... be of particular significance to long-distance seed dispersal. In Northeast Greenland, dispersal of viable seeds may frequently occur by passage through the guts of geese and musk oxen. Research at Zackenberg on the role of insects in pollination of flowering plants has shown that Diptera species, primarily flies...... Cassiope tetragona, and mountain avens Dryas octopetala are the primary species represented in the pollen present on pollinating insects at Zackenberg. The effects of climate warming that may enhance environmental conditions for plant growth in Northeast Greenland and accelerate invasion of new species...

  12. Aerobiology over Antarctica – a new initiative for atmospheric ecology

    Directory of Open Access Journals (Sweden)

    David Anthony Pearce

    2016-02-01

    Full Text Available The role of aerial dispersal in shaping patterns of biodiversity remains poorly understood, mainly due to a lack of coordinated efforts in gathering data at appropriate temporal and spatial scales. It has been long known that the rate of dispersal to an ecosystem can significantly influence ecosystem dynamics, and that aerial transport has been identified as an important source of biological input to remote locations. With the considerable effort devoted in recent decades to understanding atmospheric circulation in the south polar region, a unique opportunity has emerged to investigate the atmospheric ecology of Antarctica, from local to continental scales. This concept note identifies key questions in Antarctic microbial biogeography and the need for standardized sampling and analysis protocols to address such questions. A consortium of polar aerobiologists is established to bring together researchers with a common interest in the airborne dispersion of microbes and other propagules in the Antarctic, with opportunities for comparative studies in the Arctic.

  13. Dispersal of plant fragments in small streams

    DEFF Research Database (Denmark)

    Riis, T.; Sand-Jensen, K.

    2006-01-01

    1. Streams are subject to frequent natural and anthropogenic disturbances that cause sediment erosion and loss of submerged vegetation. This loss makes downstream transport and retention of vegetative propagules on the streambed very important for re-establishing vegetation cover. We measured...... with the relative contact between the flowing water and streambed, bank and vegetation. Thus, the retention coefficients were highest (0.02-0.12 m-1) in shallow reaches with a narrow, vegetation-free flow channel. Here there were no significant differences between E. canadensis and R. peltatus. Retention...... coefficients were lowest (0.0005-0.0135 m-1) in deeper reaches with wider vegetation-free flow channels. Retention of E. canadensis was up to 16 times more likely than retention of R. peltatus. 5. Overall, the longitudinal position in the stream system of source populations of species capable of producing...

  14. Effect of gamma radiation on Aspergillus flavus and Aspergillus ochraceus ultrastructure and mycotoxin production

    International Nuclear Information System (INIS)

    Ribeiro, J.; Cavaglieri, L.; Vital, H.; Cristofolini, A.; Merkis, C.; Astoreca, A.; Orlando, J.; Caru, M.; Dalcero, A.; Rosa, C.A.R.

    2011-01-01

    The aim of this work was to study the effect of gamma radiation (2 kGy) on Aspergillus flavus and Aspergillus ochraceus ultrastructure. Moreover, the influence on aflatoxin B 1 and ochratoxin A production was also observed. Irradiated A. flavus strain showed a dull orangish colony while control strain showed the typical green color. Minor differences were observed on stipes, metulae and conidia size between control and irradiated A. flavus and A. ochraceus strains. Irradiated fungi showed ultrastructural changes on cell wall, plasmalema and cytoplasm levels. The levels of mycotoxins produced by irradiated strains were two times greater than those produced by control strains. Successive transferences of irradiated strains on malt extract agar allowed the fungus to recuperate morphological characteristics. Although minor changes in the fungal morphology were observed, ultrastructural changes at cell wall level and the increase of mycotoxin production ability were observed. Inappropriate storage of irradiated food and feed would allow the development of potentially more toxicogenic fungal propagules.

  15. An integrative analysis of the dynamics of landscape- and local-scale colonization of Mediterranean woodlands by Pinus halepensis.

    Directory of Open Access Journals (Sweden)

    Efrat Sheffer

    Full Text Available Afforestation efforts have resulted in extensive plantations of either native or non-native conifers, which in many regions has led to the spread of those conifers into surrounding natural vegetation. This process of species colonization can trigger profound changes in both community dynamics and ecosystem processes. Our study disentangled the complexity of a process of colonization in a heterogeneous landscape into a simple set of rules. We analyzed the factors that control the colonization of natural woodland ecosystems by Pinus halepensis dispersing from plantations in the Mediterranean region of Israel. We developed maximum-likelihood models to explain the densities of P. halepensis colonizing natural woodlands. Our models unravel how P. halepensis colonization is controlled by factors that determine colonization pressure by dispersing seeds and by factors that control resistance to colonization of the natural ecosystems. Our models show that the combination of different seed arrival processes from local, landscape, and regional scales determine pine establishment potential, but the relative importance of each component varied according to seed source distribution. Habitat resistance, determined by abiotic and biotic conditions, was as important as propagule input in determining the density of pine colonization. Thus, despite the fact that pine propagules disperse throughout the landscape, habitat heterogeneity within the natural ecosystems generates significant variation in the actual densities of colonized pine. Our approach provides quantitative measures of how processes at different spatial scales affect the distribution and densities of colonizing species, and a basis for projection of expected distributions. Variation in colonization rates, due to landscape-scale heterogeneity in both colonization pressure and resistance to colonization, can be expected to produce a diversity of new ecosystems. This work provides a template for

  16. Contrasting Effects of Historical Sea Level Rise and Contemporary Ocean Currents on Regional Gene Flow of Rhizophora racemosa in Eastern Atlantic Mangroves.

    Directory of Open Access Journals (Sweden)

    Magdalene N Ngeve

    Full Text Available Mangroves are seafaring taxa through their hydrochorous propagules that have the potential to disperse over long distances. Therefore, investigating their patterns of gene flow provides insights on the processes involved in the spatial genetic structuring of populations. The coastline of Cameroon has a particular geomorphological history and coastal hydrology with complex contemporary patterns of ocean currents, which we hypothesize to have effects on the spatial configuration and composition of present-day mangroves within its spans. A total of 982 trees were sampled from 33 transects (11 sites in 4 estuaries. Using 11 polymorphic SSR markers, we investigated genetic diversity and structure of Rhizophora racemosa, a widespread species in the region. Genetic diversity was low to moderate and genetic differentiation between nearly all population pairs was significant. Bayesian clustering analysis, PCoA, estimates of contemporary migration rates and identification of barriers to gene flow were used and complemented with estimated dispersal trajectories of hourly released virtual propagules, using high-resolution surface current from a mesoscale and tide-resolving ocean simulation. These indicate that the Cameroon Volcanic Line (CVL is not a present-day barrier to gene flow. Rather, the Inter-Bioko-Cameroon (IBC corridor, formed due to sea level rise, allows for connectivity between two mangrove areas that were isolated during glacial times by the CVL. Genetic data and numerical ocean simulations indicated that an oceanic convergence zone near the Cameroon Estuary complex (CEC presents a strong barrier to gene flow, resulting in genetic discontinuities between the mangrove areas on either side. This convergence did not result in higher genetic diversity at the CEC as we had hypothesized. In conclusion, the genetic structure of Rhizophora racemosa is maintained by the contrasting effects of the contemporary oceanic convergence and historical climate

  17. Estimates of connectivity reveal non-equilibrium epiphyte occurrence patterns almost 180 years after habitat decline.

    Science.gov (United States)

    Johansson, Victor; Snäll, Tord; Ranius, Thomas

    2013-06-01

    Habitat loss is a major cause of species decline and extinction. Immediately after habitat loss, species occurrences are not in equilibrium with the new landscape and more closely reflect the previous landscape structure. Species with slow colonisation-extinction dynamics may display long time-lags before reaching a new equilibrium. We investigated the importance of connectivity to current and historical dispersal sources with the aim of explaining the occurrence pattern of epiphytic lichens with different traits among 104 old oaks. We used oak survey data collected from 1830 and 2009 for a Swedish landscape where oak densities declined drastically shortly after 1830. We fitted a commonly used connectivity measure and estimated the confidence interval for the spatial scale parameter. Small differences in the spatial scale parameter resulted in large differences in model fit. Connectivity to trees in 1830 better explained the occurrence of three of the four species compared to the connectivity in 2009. The explanatory power of the historical landscape structure was highest for the species with traits that may result in a low colonisation rate--both a narrow niche (here few suitable trees) and large dispersal propagules. The results suggest that oak-dependent epiphytic lichens have not reached equilibrium with the spatial landscape structure 180 years after the drastic decline in habitat. For the long-term persistence of epiphytes associated with old trees, conservation efforts should focus on (1) protecting and restoring stands where specialised species with large dispersal propagules (i.e. with low colonisation rates) occur today and (2) promoting tree regeneration in their near vicinity.

  18. Modified atmosphere treatments as a potential disinfestation technique for arthropod pests in greenhouses.

    Science.gov (United States)

    Held, D W; Potter, D A; Gates, R S; Anderson, R G

    2001-04-01

    Incidental transport of arthropods on plant material can be a significant mode of pest entry into greenhouses. We evaluated the use of controlled atmosphere treatments as a potential way to eliminate arthropod pests on plant propagules (i.e., cuttings or small rooted plants). Lethal exposures to CO2 or N2 were determined for common greenhouse pests including fungus gnat larvae, Bradysia sp.; green peach aphid, Myzus persicae (Sulzer); sweetpotato whitefly, Bemisia sp.; twospotted spider mite, Tetranychus urticae Koch; and western flower thrips, Frankliniella occidentalis (Pergande). We also studied the effect of pest species, life stage, and presence or absence of plants on efficacy of modified atmosphere treatments. Finally, effects of modified atmospheres on plant quality were evaluated for several bedding plant species including begonia, Begonia semperflorens-cultorum Hort. 'Cocktail Series', chrysanthemum, Dendranthema grandiflora Tzvelev., geranium, Pelargonium X hortorum L.H. Bailey, and impatiens, Impatiens wallerana Hook f., and among cultivars of geranium and chrysanthemum. Exposure for 12-18 h to >99% N2 or CO2 caused complete mortality of aphids, mites, thrips, and whiteflies. Fungus gnat larvae were more tolerant of hypoxic conditions. Adult mites and eggs were equally susceptible. For most pests, there was no difference in response to atmospheres modified by CO2 or N2. However, there was variation in response among plant species and cultivars, with effects ranging from delayed flowering to mortality. Despite the possibility of adverse effects on some plants, this work indicates that use of modified atmospheres has potential to eliminate arthropod pests on plant propagules before they are introduced into greenhouses.

  19. Red mangrove (Rhizophora mangle) reproduction and seedling colonization after Hurricane Charley: Comparisons of Charlotte Harbor and Tampa Bay

    Science.gov (United States)

    Proffitt, C.E.; Milbrandt, E.C.; Travis, S.E.

    2006-01-01

    Reproductive aspects of life history are known to be important in recovery following disturbance in many plant species although this has not been well studied in mangroves. Hurricane Charley devastated large areas of mangroves in Charlotte Harbor, Florida, in August 2004. We surveyed 6 forests in Charlotte Harbor (2002, 2003, and 2005) and 16 in Tampa Bay, Florida (2001, 2002, 2003, and 2005) for total numbers of reproducing trees and trees heterozygotic for albinism that produce both normal and albino propagules. Tree size (estimated height and diameter at breast height) was also recorded for sentinel heterozygotic trees. Total number of reproducing trees km-1 was used as an index of reproductive output of the population, and deviation from the 3:1 (normal:albino propagules) ratio on heterozygotic trees expected with 100% selfing was used to estimate outcrossing. Numbers of Rhizophora mangle reproducing trees km-1 of shoreline in Charlotte Harbor were reduced by an order of magnitude following Hurricane Charley, while numbers of reproducing trees in Tampa Bay were similar to those of previous years. Reduced reproduction in Charlotte Harbor was accompanied by fewer new recruits in plots on Sanibel and Captiva Islands. Numbers of new recruits after the storm also tended to be fewer in plots where canopy loss was greater. More new recruits occurred in sites that had higher densities of pre-storm Rhizophora seedlings and greater relative dominance by Rhizophora. Outcrossing of sentinel trees was 2.5 times greater in Charlotte Harbor (mean site-1 = 33.6 ?? 6.7%; with 17% of forest sites completely selfing) than in Tampa Bay (mean site-1 = 13.4 ?? 4.7%; with 40% of sites completely selfing), although the implications for seedling recruitment of this difference are not known. ?? 2006 Estuarine Research Federation.

  20. A restoration genetics guide for coral reef conservation.

    Science.gov (United States)

    Baums, Iliana B

    2008-06-01

    Worldwide degradation of coral reef communities has prompted a surge in restoration efforts. They proceed largely without considering genetic factors because traditionally, coral populations have been regarded as open over large areas with little potential for local adaptation. Since, biophysical and molecular studies indicated that most populations are closed over shorter time and smaller spatial scales. Thus, it is justified to re-examine the potential for site adaptation in corals. There is ample evidence for differentiated populations, inbreeding, asexual reproduction and the occurrence of ecotypes, factors that may facilitate local adaptation. Discovery of widespread local adaptation would influence coral restoration projects mainly with regard to the physical and evolutionary distance from the source wild and/or captive bred propagules may be moved without causing a loss of fitness in the restored population. Proposed causes for loss of fitness as a result of (plant) restoration efforts include founder effects, genetic swamping, inbreeding and/or outbreeding depression. Direct evidence for any of these processes is scarce in reef corals due to a lack of model species that allow for testing over multiple generations and the separation of the relative contributions of algal symbionts and their coral hosts to the overall performance of the coral colony. This gap in our knowledge may be closed by employing novel population genetic and genomics approaches. The use of molecular tools may aid managers in the selection of appropriate propagule sources, guide spatial arrangement of transplants, and help in assessing the success of coral restoration projects by tracking the performance of transplants, thereby generating important data for future coral reef conservation and restoration projects.

  1. Pathways of fish invasions in the Mid-Atlantic region of the United States

    Science.gov (United States)

    Lapointe, Nicolas W. R.; Fuller, Pam; Neilson, Matthew; Murphy, Brian R.; Angermeier, Paul

    2016-01-01

    Non-native fish introductions are a major threat to biodiversity and fisheries, and occur through numerous pathways that vary regionally in importance. A key strategy for managing invasions is to focus prevention efforts on pathways posing the greatest risk of future introductions. We identified high-risk pathways for fish establishment in the Mid-Atlantic region of the United States based on estimates of probability of establishment and records of previous introductions, which were considered in the context of emerging socioeconomic trends. We used estimates of propagule pressure, species’ environmental tolerance, and size of species pool to assess the risk of establishment by pathway. Pathways varied considerably in historic importance and species composition, with the majority of species introduced intentionally via stocking (primarily for sport, forage, or biocontrol) or bait release. Bait release, private stocking, illegal introductions intended to establish reproducing populations (e.g., of sport fish), aquaculture, and the sale of live organisms all create risks for future invasions in the Mid-Atlantic region. Of these pathways, bait release probably poses the greatest risk of introductions for the Mid-Atlantic region because propagule pressure is moderate, most released species are tolerant of local environmental conditions, and the pool of species available for transplantation is large. Our findings differ considerably from studies in other regions (e.g., bait release is a dominant pathway in the Mid-Atlantic region, whereas illegal introduction of sport fish is dominant in the western US and aquarium releases are dominant in Florida), demonstrating the need for regional-scale assessments of, and management strategies for, introduction pathways.

  2. Predicting the cumulative effect of multiple disturbances on seagrass connectivity.

    Science.gov (United States)

    Grech, Alana; Hanert, Emmanuel; McKenzie, Len; Rasheed, Michael; Thomas, Christopher; Tol, Samantha; Wang, Mingzhu; Waycott, Michelle; Wolter, Jolan; Coles, Rob

    2018-03-15

    The rate of exchange, or connectivity, among populations effects their ability to recover after disturbance events. However, there is limited information on the extent to which populations are connected or how multiple disturbances affect connectivity, especially in coastal and marine ecosystems. We used network analysis and the outputs of a biophysical model to measure potential functional connectivity and predict the impact of multiple disturbances on seagrasses in the central Great Barrier Reef World Heritage Area (GBRWHA), Australia. The seagrass networks were densely connected, indicating that seagrasses are resilient to the random loss of meadows. Our analysis identified discrete meadows that are important sources of seagrass propagules and that serve as stepping stones connecting various different parts of the network. Several of these meadows were close to urban areas or ports and likely to be at risk from coastal development. Deep water meadows were highly connected to coastal meadows and may function as a refuge, but only for non-foundation species. We evaluated changes to the structure and functioning of the seagrass networks when one or more discrete meadows were removed due to multiple disturbance events. The scale of disturbance required to disconnect the seagrass networks into two or more components was on average >245 km, about half the length of the metapopulation. The densely connected seagrass meadows of the central GBRWHA are not limited by the supply of propagules; therefore, management should focus on improving environmental conditions that support natural seagrass recruitment and recovery processes. Our study provides a new framework for assessing the impact of global change on the connectivity and persistence of coastal and marine ecosystems. Without this knowledge, management actions, including coastal restoration, may prove unnecessary and be unsuccessful. © 2018 John Wiley & Sons Ltd.

  3. Expansion of a globally pervasive grass occurs without substantial trait differences between home and away populations.

    Science.gov (United States)

    Leifso, A; MacDougall, A S; Husband, B; Hierro, J L; Köchy, M; Pärtel, M; Peltzer, D A

    2012-12-01

    The global expansion of species beyond their ancestral ranges can derive from mechanisms that are trait-based (e.g., post-establishment evolved differences compared to home populations) or circumstantial (e.g., propagule pressure, with no trait-based differences). These mechanisms can be difficult to distinguish following establishment, but each makes unique predictions regarding trait similarity between ancestral ('home') and introduced ('away') populations. Here, we tested for trait-based population differences across four continents for the globally distributed grass Dactylis glomerata, to assess the possible role of trait evolution in its worldwide expansion. We used a common-environment glasshouse experiment to quantify trait differences among home and away populations, and the potential relevance of these differences for competitive interactions. Few significant trait differences were found among continents, suggesting minimal change during global expansion. All populations were polyploids, with similar foliar carbon:nitrogen ratios (a proxy for defense), chlorophyll content, and biomass. Emergence time and growth rate favored home populations, resulting in their competitive superiority over away populations. Small but significant trait differences among away populations suggest different introductory histories or local adaptive responses following establishment. In summary, the worldwide distribution of this species appears to have arisen from its pre-adapted traits promoting growth, and its repeated introduction with cultivation and intense propagule pressure. Global expansion can thus occur without substantial shifts in growth, reproduction, or defense. Rather than focusing strictly on the invader, invasion success may also derive from the traits found (or lacking) in the recipient community and from environmental context including human disturbance.

  4. Antarctic fellfield response to climate change: a tripartite synthesis of experimental data.

    Science.gov (United States)

    Kennedy, Andrew D

    1996-07-01

    This paper explores the biological consequences of climate change by integrating the results of a tripartite investigation involving fumarole, field manipulation and laboratory incubation experiments. The geographical region for this research is the maritime Antarctic. Under contemporary climate conditions, the lithosols in this region support only a sparse cryptogamic flora of limited taxonomic diversity and low structural complexity. However, the existence in geothermal areas of temperate species (e.g. Campylopus introflexus, Marchantia polymorpha, Philonotis acicularis) growing outside their normal biogeographical range suggests that elevated temperature and humidity may alter the trajectory of community development towards Magellanic or Patagonian composition. Productivity is also likely to increase, as indicated by significantly greater vegetative biomass recorded beneath climate-ameliorating soil covers than in controls. Barren fellfield soil samples transplanted to the laboratory and incubated at temperatures of 2-25°C show rapid development of moss, algae and lichen propagules in the range 15-25°C. A variety of species develop that have not been recorded in the field. The presence of exotic taxa indicates the existence of a dormant propagule bank in maritime Antarctic soils and suggests that no significant delay is likely to occur between the onset of climate warming and community development: instead, rapid establishment of those species favoured by the new climate conditions will yield a distinct founder effect, with increasing above- and below-ground biomass stimulating biogeochemical cycling. It is argued that the combined results of this synthesis identify generic responses to climate change arising from the importance at high latitudes of low temperature and water availability as limiting factors: subject to other growth resources being non-limiting, a more consistent stimulatory response to climate change may be expected than in temperate or

  5. Fungal monitoring of the indoor air of the Museo de La Plata Herbarium, Argentina.

    Science.gov (United States)

    Mallo, Andrea C; Elíades, Lorena A; Nitiu, Daniela S; Saparrat, Mario C N

    Biological agents, such as fungal spores in the air in places where scientific collections are stored, can attack and deteriorate them. The aim of this study was to gather information on the indoor air quality of the Herbarium of Vascular Plants of the Museo de Ciencias Naturales de La Plata, Argentina, in relation to fungal propagules and inert particles. This study was made using a volumetric system and two complementary sampling methods: (1) a non-viable method for direct evaluation, and (2) a viable method by culture for viable fungal propagules. The non-viable method led to ten spore morphotypes being found from related fungal sources. A total of 4401.88spores/m 3 and 32135.18 inert suspended particles/m 3 were recorded. The viable method led to the finding of nine fungal taxa as viable spores that mostly belonged to anamorphic forms of Ascomycota, although the pigmented yeast Rhodotorula F.C. Harrison (Basidiomycota) was also found. A total count of 40,500fungal CFU/m 3 air was estimated for all the sites sampled. Both the non-viable and viable sampling methods were necessary to monitor the bio-aerosol load in the La Plata Herbarium. The indoor air of this institution seems to be reasonably adequate for the conservation of vascular plants due to the low indoor/outdoor index, low concentrations of air spores, and/or lack of indicators of moisture problems. Copyright © 2016 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

  6. Snowpack, fire, and forest disturbance: interactions affect montane invasions by non-native shrubs.

    Science.gov (United States)

    Stevens, Jens T; Latimer, Andrew M

    2015-06-01

    Montane regions worldwide have experienced relatively low plant invasion rates, a trend attributed to increased climatic severity, low rates of disturbance, and reduced propagule pressure relative to lowlands. Manipulative experiments at elevations above the invasive range of non-native species can clarify the relative contributions of these mechanisms to montane invasion resistance, yet such experiments are rare. Furthermore, global climate change and land use changes are expected to cause decreases in snowpack and increases in disturbance by fire and forest thinning in montane forests. We examined the importance of these factors in limiting montane invasions using a field transplant experiment above the invasive range of two non-native lowland shrubs, Scotch broom (Cytisus scoparius) and Spanish broom (Spartium junceum), in the rain-snow transition zone of the Sierra Nevada of California. We tested the effects of canopy closure, prescribed fire, and winter snow depth on demographic transitions of each species. Establishment of both species was most likely at intermediate levels of canopy disturbance, but at this intermediate canopy level, snow depth had negative effects on winter survival of seedlings. We used matrix population models to show that an 86% reduction in winter snowfall would cause a 2.8-fold increase in population growth rates in Scotch broom and a 3.5-fold increase in Spanish broom. Fall prescribed fire increased germination rates, but decreased overall population growth rates by reducing plant survival. However, at longer fire return intervals, population recovery between fires is likely to keep growth rates high, especially under low snowpack conditions. Many treatment combinations had positive growth rates despite being above the current invasive range, indicating that propagule pressure, disturbance, and climate can all strongly affect plant invasions in montane regions. We conclude that projected reductions in winter snowpack and increases in

  7. Evaluating Hypotheses of Plant Species Invasions on Mediterranean Islands: Inverse Patterns between Alien and Endemic Species

    Directory of Open Access Journals (Sweden)

    Alexander Bjarnason

    2017-08-01

    Full Text Available Invasive alien species cause major changes to ecosystem functioning and patterns of biodiversity, and the main factors involved in invasion success remain contested. Using the Mediterranean island of Crete, Greece as a case study, we suggest a framework for analyzing spatial data of alien species distributions, based on environmental predictors, aiming to gain an understanding of their spatial patterns and spread. Mediterranean islands are under strong ecological pressure from invading species due to their restricted size and increased human impact. Four hypotheses of invasibility, the “propagule pressure hypothesis” (H1, “biotic resistance hypothesis vs. acceptance hypothesis” (H2, “disturbance-mediated hypothesis” (H3, and “environmental heterogeneity hypothesis” (H4 were tested. Using data from alien, native, and endemic vascular plant species, the propagule pressure, biotic resistance vs. acceptance, disturbance-mediated, and environmental heterogeneity hypotheses were tested with Generalized Additive Modeling (GAM of 39 models. Based on model selection, the optimal model includes the positive covariates of native species richness, the negative covariates of endemic species richness, and land area. Variance partitioning between the four hypotheses indicated that the biotic resistance vs. acceptance hypothesis explained the vast majority of the total variance. These results show that areas of high species richness have greater invasibility and support the acceptance hypothesis and “rich-get-richer” distribution of alien species. The negative correlation between alien and endemic species appears to be predominantly driven by altitude, with fewer alien and more endemic species at greater altitudes, and habitat richness. The negative relationship between alien and endemic species richness provides potential for understanding patterns of endemic and alien species on islands, contributing to more effective conservation

  8. Atlantic forests to the all Americas: Biogeographical history and divergence times of Neotropical Ficus (Moraceae).

    Science.gov (United States)

    Machado, Anderson Ferreira Pinto; Rønsted, Nina; Bruun-Lund, Sam; Pereira, Rodrigo Augusto Santinelo; Paganucci de Queiroz, Luciano

    2018-05-01

    Ficus (Moraceae) is well diversified in the Neotropics with two lineages inhabiting the wet forests of this region. The hemiepiphytes of section Americanae are the most diversified with c. 120 species, whereas section Pharmacosycea includes about 20 species mostly with a terrestrial habit. To reconstruct the biogeographical history and diversification of Ficus in the Americas, we produced a dated Bayesian phylogenetic hypothesis of Neotropical Ficus including two thirds of the species sequenced for five nuclear regions (At103, ETS, G3pdh, ITS/5.8S and Tpi). Ancestral range was estimated using all models available in Biogeobears and Binary State Speciation and Extinction analysis was used to evaluate the role of the initial habit and propagule size in diversification. The phylogenetic analyses resolved both Neotropical sections as monophyletic but the internal relationships between species in section Americanae remain unclear. Ficus started their diversification in the Neotropics between the Oligocene and Miocene. The genus experienced two bursts of diversification: in the middle Miocene and the Pliocene. Colonization events from the Amazon to adjacent areas coincide with the end of the Pebas system (10 Mya) and the connection of landmasses. Divergence of endemic species in the Atlantic forest is inferred to have happened after its isolation and the opening and consolidation of the Cerrado. Our results suggest a complex diversification in the Atlantic forest differing between postulated refuges and more instable areas in the South distribution of the forest. Finally the selection for initial hemiepiphytic habit and small to medium propagule size influenced the diversification and current distribution of the species at Neotropical forests marked by the historical instability and long-distance dispersal. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. A tough egg to crack: recreational boats as vectors for invasive goby eggs and transdisciplinary management approaches.

    Science.gov (United States)

    Hirsch, Philipp E; Adrian-Kalchhauser, Irene; Flämig, Sylvie; N'Guyen, Anouk; Defila, Rico; Di Giulio, Antonietta; Burkhardt-Holm, Patricia

    2016-02-01

    Non-native invasive species are a major threat to biodiversity, especially in freshwater ecosystems. Freshwater ecosystems are naturally rather isolated from one another. Nonetheless, invasive species often spread rapidly across water sheds. This spread is to a large extent realized by human activities that provide vectors. For example, recreational boats can carry invasive species propagules as "aquatic hitch-hikers" within and across water sheds. We used invasive gobies in Switzerland as a case study to test the plausibility that recreational boats can serve as vectors for invasive fish and that fish eggs can serve as propagules. We found that the peak season of boat movements across Switzerland and the goby spawning season overlap temporally. It is thus plausible that goby eggs attached to boats, anchors, or gear may be transported across watersheds. In experimental trials, we found that goby eggs show resistance to physical removal (90 mN attachment strength of individual eggs) and stay attached if exposed to rapid water flow (2.8 m·s(-1)for 1 h). When exposing the eggs to air, we found that hatching success remained high (>95%) even after eggs had been out of water for up to 24 h. It is thus plausible that eggs survive pick up, within-water and overland transport by boats. We complemented the experimental plausibility tests with a survey on how decision makers from inside and outside academia rate the feasibility of managing recreational boats as vectors. We found consensus that an installation of a preventive boat vector management is considered an effective and urgent measure. This study advances our understanding of the potential of recreational boats to serve as vectors for invasive vertebrate species and demonstrates that preventive management of recreational boats is considered feasible by relevant decision makers inside and outside academia.

  10. Influence of protoplast fusion between two Trichoderma spp. on extracellular enzymes production and antagonistic activity.

    Science.gov (United States)

    Hassan, Mohamed M

    2014-11-02

    Biological control plays a crucial role in grapevine pathogens disease management. The cell-wall degrading enzymes chitinase, cellulase and β-glucanase have been suggested to be essential for the mycoparasitism activity of Trichoderma species against grapevine fungal pathogens. In order to develop a useful strain as a single source of these vital enzymes, it was intended to incorporate the characteristics of two parental fungicides tolerant mutants of Trichoderma belonging to the high chitinase producing species T. harzianum and the high cellulase producing species T. viride , by fusing their protoplasts. The phylogeny of the parental strains was carried out using a sequence of the 5.8S-ITS region. The BLAST of the obtained sequence identified these isolates as T. harzianum and T. viride . Protoplasts were isolated using lysing enzymes and were fused using polyethylene glycol. The fused protoplasts have been regenerated on protoplast regeneration minimal medium supplemented with two selective fungicides. Among the 40 fast growing fusants, 17 fusants were selected based on their enhanced growth on selective media for further studies. The fusant strains were growing 60%-70% faster than the parents up to third generation. All the 17 selected fusants exhibited morphological variations. Some fusant strains displayed threefold increased chitinase enzyme activity and twofold increase in β-glucanase enzyme activity compared to the parent strains. Most fusants showed powerful antagonistic activity against Macrophomin aphaseolina , Pythium ultimum and Sclerotium rolfsii pathogens. Fusant number 15 showed the highest inhibition percentage (92.8%) against M. phaseolina and P. ultimum, while fusant number 9 showed the highest inhibition percentage (98.2%) against the growth of S. rolfsii. A hyphal intertwining and degradation phenomenon was observed by scanning electron microscope. The Trichoderma antagonistic effect against pathogenic fungal mycelia was due to the

  11. The normal mycoflora of commodities from Thailand. 1. Nuts and oilseeds.

    Science.gov (United States)

    Pitt, J I; Hocking, A D; Bhudhasamai, K; Miscamble, B F; Wheeler, K A; Tanboon-Ek, P

    1993-12-01

    A comprehensive study was carried out of the fungi occurring in commodities normally traded in Thailand. Samples of major commodities were obtained from farmers' stocks and middlemen in major producing areas throughout the country. Retail samples were obtained from outlets in and around Bankok. Samples were divided into two portions, one being examined in Bangkok, and the second in Sydney. After surface disinfection, fungi were enumerated by direct plating on dichloran rose bengal chloramphenicol agar, dichloran 18% glycerol agar, Aspergillus flavus and parasiticus agar and dichloran chloramphenicol peptone agar. Figures for percentage infection were calculated, and fungi were isolated and identified to species level. In all 602 samples were examined, and at North Ryde about 18,000 fungal isolates identified. Data obtained from 329 samples are reported here, comprising maize (154), peanuts (109), cashews (45) and copra (21). Major fungi in maize included Fusarium moniliforme (present in 97% of samples), Aspergillus flavus (85%), Penicillium citrinum (67%), Aspergillus niger (64%), Lasiodiplodia theobromae (58%) and Fusarium semitectum (45%). In peanuts, the major fungi were Aspergillus flavus (95% of samples), Aspergillus niger (86%), Rhizopus oryzae (60%), Eurotium rubrum (51%), Macromina phaseolina (49%), Penicillium citrinum (46%) and Eurotium chevalieri (46%). Invasion in cashews was lower, major fungi being Aspergillus flavus (60%), Nigrospora oryzae (58%), Aspergillus niger (53%), Chaetomium globosum (47%) and Eurotium chevalieri (40%). Aspergillus flavus (86% of samples) was again dominant in copra, with Rhizopus oryzae (52%), Aspergillus niger (43%), Eurotium chevalieri (43%) the only other species exceeding 40% infection. Aspergillus parasiticus was rarely seen, and Aspergillus nomius was reported from foods for the first time.

  12. Chemical composition and antifungal activity of thyme (Thymus vulgaris essential oil

    Directory of Open Access Journals (Sweden)

    S. Farsaraei*

    2017-11-01

    Full Text Available Background and objectives: The antifungal activity of the essential oils and their constituents against some phytopathogenic fungi has been reported. Thymus vulgaris (Lamiaceae is one of the Thymus species.  A large number of studies have concerned the chemical compositions and antifungal activity of thyme’s oil. In order to reduce the use of synthetic fungicides, recently considerable attention has been given to search for naturally occurring compounds. The aim of the present work was to determine the chemical composition and antifungal activity of T. vulgaris oil cultivated in Iran. Methods: The essential oil from aerial parts of the plant at full flowering stage was subjected to hydrodistillation and chemical compounds were analyzed by GC/GC-MS. The in vitro antifungal activity against three phytopathogenic fungi (Drechslera spicifera, Fusarium oxysporum f.sp. ciceris and Macrophomina phaseolinaby of the oil was evaluated by agar dilution method. The data were subjected to ANOVA according to the SPSS 21 software. Results: Totally 45 compounds representing 96.75% of the oil were found. Thymol (36.81% and ρ-cymene (30.90% were the main components of thyme oil. According to the results, the antifungal activity of the oil increased with a rising in concentration. All of the tested fungi growth was completely inhibited on 1600 µL/L. In this study fungicidal activity was only observed on F. oxysporum and D. spicifera at concentrations higher than 800 µL/L.  Conclusion: The antifungal activity of T. vulgaris essential oil could be probably due to the high concentration of oxygenated monoterpenes (thymol and monoterpene hydrocarbons (ρ-cymene.

  13. Genomic Tools in Cowpea Breeding Programs: Status and Perspectives

    Science.gov (United States)

    Boukar, Ousmane; Fatokun, Christian A.; Huynh, Bao-Lam; Roberts, Philip A.; Close, Timothy J.

    2016-01-01

    Cowpea is one of the most important grain legumes in sub-Saharan Africa (SSA). It provides strong support to the livelihood of small-scale farmers through its contributions to their nutritional security, income generation and soil fertility enhancement. Worldwide about 6.5 million metric tons of cowpea are produced annually on about 14.5 million hectares. The low productivity of cowpea is attributable to numerous abiotic and biotic constraints. The abiotic stress factors comprise drought, low soil fertility, and heat while biotic constraints include insects, diseases, parasitic weeds, and nematodes. Cowpea farmers also have limited access to quality seeds of improved varieties for planting. Some progress has been made through conventional breeding at international and national research institutions in the last three decades. Cowpea improvement could also benefit from modern breeding methods based on molecular genetic tools. A number of advances in cowpea genetic linkage maps, and quantitative trait loci associated with some desirable traits such as resistance to Striga, Macrophomina, Fusarium wilt, bacterial blight, root-knot nematodes, aphids, and foliar thrips have been reported. An improved consensus genetic linkage map has been developed and used to identify QTLs of additional traits. In order to take advantage of these developments single nucleotide polymorphism (SNP) genotyping is being streamlined to establish an efficient workflow supported by genotyping support service (GSS)-client interactions. About 1100 SNPs mapped on the cowpea genome were converted by LGC Genomics to KASP assays. Several cowpea breeding programs have been exploiting these resources to implement molecular breeding, especially for MARS and MABC, to accelerate cowpea variety improvement. The combination of conventional breeding and molecular breeding strategies, with workflow managed through the CGIAR breeding management system (BMS), promises an increase in the number of improved

  14. Genomic tools in cowpea breeding programs: status and perspectives

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    Ousmane eBoukar

    2016-06-01

    Full Text Available Cowpea is one of the most important grain legumes in sub-Saharan Africa (SSA. It provides strong support to the livelihood of small-scale farmers through its contributions to their nutritional security, income generation and soil fertility enhancement. Worldwide about 6.5 million metric tons of cowpea are produced annually on about 14.5 million hectares. The low productivity of cowpea is attributable to numerous abiotic and biotic constraints. The abiotic stress factors comprise drought, low soil fertility, and heat while biotic constraints include insects, diseases, parasitic weeds and nematodes. Cowpea farmers also have limited access to quality seeds of improved varieties for planting. Some progress has been made through conventional breeding at international and national research institutions in the last three decades. Cowpea improvement could also benefit from modern breeding methods based on molecular genetic tools. A number of advances in cowpea genetic linkage maps, and quantitative trait loci associated with some desirable traits such as resistance to Striga, Macrophomina, Fusarium wilt, bacterial blight, root-knot nematodes, aphids and foliar thrips have been reported. An improved consensus genetic linkage map has been developed and used to identify QTLs of additional traits. In order to take advantage of these developments single nucleotide polymorphism (SNP genotyping is being streamlined to establish an efficient workflow supported by genotyping support service (GSS-client interactions. About 1100 SNPs mapped on the cowpea genome were converted by LGC Genomics to KASP assays. Several cowpea breeding programs have been exploiting these resources to implement molecular breeding, especially for MARS and MABC, to accelerate cowpea variety improvement. The combination of conventional breeding and molecular breeding strategies, with workflow managed through the CGIAR breeding management system (BMS, promises an increase in the number of

  15. INFLUÊNCIA DA DENSIDADE DE INÓCULO DE Fusarium solani f.sp. phaseoli NA SEVERIDADE DA PODRIDÃO RADICULAR SECA DO FEIJOEIRO EFFECT OF Fusarium solani f.sp. phaseoli INOCULUM DENSITY ON DRY ROOT ROT SEVERITY IN THE COMMON BEAN

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    Gesimária Ribeiro Costa

    2007-09-01

    Full Text Available

    Foram testadas quatro densidades de inóculo de Fusarium solani, em gramas por litro de solo (1,0; 2,0; 4,0 e 8,0 e um tratamento testemunha, em solo tipo Latossolo Vermelho-Escuro, cultivado e não cultivado, com o objetivo de determinar a densidade mínima de inóculo no solo necessária para a ocorrência de podridão radicular seca do feijoeiro. Como variáveis respostas foram avaliadas: número de microorganismos totais do solo, número de propágulos de F. solani, atividade microbiológica total do solo e severidade da doença em plântulas. Os resultados indicaram que a densidade de inóculo do fungo variou com o tipo de solo. Para um solo não cultivado a densidade necessária para causar a doença esteve acima de 5.127 propágulos por grama de solo, enquanto para o solo cultivado a densidade de inóculo para causar doença foi de 3.701 propágulos por grama de solo. Os índices de doença em plântulas cultivadas sob o solo cultivado foram duas vezes superiores ao índice de doença de plântulas sob o solo não cultivado. A atividade microbiológica total nos solos, determinada pela desidrogenase de fluorescina diacetato, não se correlacionou com a população dos microorganismos, indicando que a simples presença desses não implica em que estejam ativos.

    PALAVRAS-CHAVE: Solo supressivo; solo conducivo; Phaseolus vulgaris.

    Four densities of Fusarium solani inoculum (1, 2, 4 and 8 g/L of soil were tested for determining the minimum inoculum density for the occurrence of bean dry root rot, in two soil types. The response variables evaluated were the total number of microorganisms in the soil, the number of F. solani f. sp. phaseoli propagules, total soil microbial activity and seedling disease severity

  16. DIVERSIDAD DE HONGOS MICORRIZÓGENOS ARBUSCULARES DE UNA CRONO-SECUENCIA DE SUELOS ALUVIALES DEGRADADOS POR ACTIVIDAD MINERA EN EL BAJO CAUCA ANTIOQUEÑO, COLOMBIA DIVERSITY OF ARBUSCULAR MYCORRHIZAL FUNGI IN A CHRONO-SEQUENCE OF ALLUVIAL AND DEGRADED SOILS DUE TO MINING PROCESSES IN BAJO CAUCA ANTIOQUEÑO, COLOMBIA

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    Marisol Medina Sierra

    2009-06-01

    undisturbed and disturbed soils form alluvial mining processes. The soils belong to the Tropic Fluvaquent, Typic Dystropept, and Typic Paleudult sub-groups which corresponded to Low, Middle and High terraces, respectively, of the Cauca river at Taraza town. AMF propagules were multiplied in Leonard jars under glasshouse conditions using sterile substrate, modified Hoagland's solution and different fractions of soil used as sources of inoculum, which corresponded to the size of the spores. A first assay was made in maize (Zea mays which allowed mycorrhizal colonization in roots but not spore production. In a second assay, in kudzú (Pueraria phaseoloides AMF spores and colonized roots were obtained with the treatments corresponding to propagules obtained from high terrace and disturbed soil. These treatments presented a significant effect on kudzu yield (P≤0,001 respect to the other treatments. The AMF spores of undisturbed and disturbed soils showed low infective capacity. Nevertheless, propagules of AMF were multiplied in trap cultures, which produced spores of four morphotypes. One of these was identified as G. microagregatum. The polymorphism obtained by RAPD's made possible the differentiation of these morphotypes with the primer OPA2. Similitude above 38% was achieved using UPGMA system. The results indicated that four morphotypes belong to the genus Glomus, but they possibly belong to different species. Our results are promissory in the differentiation of native strains of AMF with low number of spores collected from soil samples in rehabilitation processes, which normally is unknown.

  17. Colecta de Jatropha curcas y su comportamiento en fase de vivero y de establecimiento (Nota técnica Collection of Jatropha curcas and its performance in nursery and establishment stages (Technical note

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    R Machado

    2011-06-01

    Full Text Available El objetivo de este trabajo fue colectar material de J. curcas con características morfológicas adecuadas para la producción de semilla, así como determinar su comportamiento en la fase de vivero y la de establecimiento. En el vivero se observó variación en los días necesarios para el arraigamiento de los propágulos (14 a 35 días y en la emergencia de las plántulas (7 a 28 días. La supervivencia de los propágulos fluctuó entre 73 y 100%; mientras que a partir de semilla estuvo entre 26,6 y 85,0%. La supervivencia en la fase de campo varió entre 45,4 y 93,3% en las procedencias trasladadas por propágulos, pero en la mayoría resultó inferior a la que se detectó en el vivero. En las procedencias sembradas directamente también se detectó variación en la supervivencia, pero el número de plantas emergidas a los 56 días fue alto. En estas condiciones se mantuvo un patrón de variación similar en el porcentaje de plantas arraigadas y de supervivencia, pero fue evidente el efecto del estrés causado por el traslado. Se concluye que la edad de las plantas y de las partes elegidas en el material donante, así como la calidad de la semilla, pudieron influir en la variación de los días necesarios para el arraigamiento o la emergencia y en el porcentaje de supervivencia. Se recomienda utilizar el procedimiento descrito para la colecta de J. curcas, enfatizando en la vía vegetativa, con el fin de acceder a procedencias con características adecuadas para la producción de semilla y con ello mantener el genotipo de los materiales colectados.The objective of this work was to collect J. curcas material with adequate morphological characteristics for seed production, as well as to determine its performance in the nursery and establishment stages. In nursery variation was observed in the necessary days for the rooting of the propagules (14 to 35 days and in seedling emergence (7 to 28 days. The propagule survival fluctuated between 73 and

  18. Potential for Extensive Forest Loss in the Klamath Mountains due to Increased Fire Activity and Altered Post-Fire Forest Recovery Dynamics in a Warming Climate

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    Tepley, A. J.; Thompson, J. R.; Epstein, H. E.; Anderson-Teixeira, K. J.

    2016-12-01

    In the context of ongoing climatic warming, certain landscapes could be near a tipping point where relatively small changes to their fire regimes or post-fire forest recovery dynamics could bring about extensive conversion of forests to shorter-statured, more fire-prone vegetation, with associated changes in biodiversity, carbon dynamics, and climate feedbacks. Such concerns are particularly valid in the Klamath Region of northern California and southwestern Oregon, where montane landscapes support conifer forests, but severe fire converts them to systems dominated by broadleaf trees and shrubs that rapidly resprout or germinate from a dormant seedbank. Conifers eventually overtop the competing vegetation, but until they do, these systems are highly fire prone and susceptible to perpetuation through a cycle of reburning. To assess the vulnerability to fire-driven loss of conifer forests in a warming climate, we characterized the trajectories of post-fire forest recovery in 57 sites that burned severely within the last three decades and span the aridity gradient of montane conifer forests. Post-fire conifer regeneration was limited to a surprisingly narrow window, with 89% of all seedlings established in the first four years after fire. Early establishment conferred a competitive growth advantage such that the longer the lag between the fire year and the year of seedling establishment, the slower its height growth. A substantial portion of variation in post-fire conifer seedling density was driven by an interaction between propagule pressure and site moisture status (climatic water deficit). Mesic sites had abundant regeneration except where seed sources were nearly absent across large (ca. 50 ha) high-severity patches. Toward the dry end of the moisture gradient, much higher propagule pressure was required to support even moderate levels of conifer regeneration. The present distribution of conifer forests falls largely within the portion of the moisture gradient

  19. Risk spreading, connectivity, and optimal reserve spacing.

    Science.gov (United States)

    Blowes, Shane A; Connolly, Sean R

    2012-01-01

    Two important processes determining the dynamics of spatially structured populations are dispersal and the spatial covariance of demographic fluctuations. Spatially explicit approaches to conservation, such as reserve networks, must consider the tension between these two processes and reach a balance between distances near enough to maintain connectivity, but far enough to benefit from risk spreading. Here, we model this trade-off. We show how two measures of metapopulation persistence depend on the shape of the dispersal kernel and the shape of the distance decay in demographic covariance, and we consider the implications of this trade-off for reserve spacing. The relative rates of distance decay in dispersal and demographic covariance determine whether the long-run metapopulation growth rate, and quasi-extinction risk, peak for adjacent patches or intermediately spaced patches; two local maxima in metapopulation persistence are also possible. When dispersal itself fluctuates over time, the trade-off changes. Temporal variation in mean distance that propagules are dispersed (i.e., propagule advection) decreases metapopulation persistence and decreases the likelihood that persistence will peak for adjacent patches. Conversely, variation in diffusion (the extent of random spread around mean dispersal) increases metapopulation persistence overall and causes it to peak at shorter inter-patch distances. Thus, failure to consider temporal variation in dispersal processes increases the risk that reserve spacings will fail to meet the objective of ensuring metapopulation persistence. This study identifies two phenomena that receive relatively little attention in empirical work on reserve spacing, but that can qualitatively change the effectiveness of reserve spacing strategies: (1) the functional form of the distance decay in covariance among patch-specific demographic rates and (2) temporal variation in the shape of the dispersal kernel. The sensitivity of metapopulation

  20. Species distribution and introgressive hybridization of two Avicennia species from the Western Hemisphere unveiled by phylogeographic patterns.

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    Mori, Gustavo M; Zucchi, Maria I; Sampaio, Iracilda; Souza, Anete P

    2015-04-10

    Mangrove plants grow in the intertidal zone in tropical and subtropical regions worldwide. The global latitudinal distribution of the mangrove is mainly influenced by climatic and oceanographic features. Because of current climate changes, poleward range expansions have been reported for the major biogeographic regions of mangrove forests in the Western and Eastern Hemispheres. There is evidence that mangrove forests also responded similarly after the last glaciation by expanding their ranges. In this context, the use of genetic tools is an informative approach for understanding how historical processes and factors impact the distribution of mangrove species. We investigated the phylogeographic patterns of two Avicennia species, A. germinans and A. schaueriana, from the Western Hemisphere using nuclear and chloroplast DNA markers. Our results indicate that, although Avicennia bicolor, A. germinans and A. schaueriana are independent lineages, hybridization between A. schaueriana and A. germinans is a relevant evolutionary process. Our findings also reinforce the role of long-distance dispersal in widespread mangrove species such as A. germinans, for which we observed signs of transatlantic dispersal, a process that has, most likely, contributed to the breadth of the distribution of A. germinans. However, along the southern coast of South America, A. schaueriana is the only representative of the genus. The distribution patterns of A. germinans and A. schaueriana are explained by their different responses to past climate changes and by the unequal historical effectiveness of relative gene flow by propagules and pollen. We observed that A. bicolor, A. germinans and A. schaueriana are three evolutionary lineages that present historical and ongoing hybridization on the American continent. We also inferred a new evidence of transatlantic dispersal for A. germinans, which may have contributed to its widespread distribution. Despite the generally wider distribution of A

  1. Disrupting mycorrhizal mutualisms: a potential mechanism by which exotic tamarisk outcompetes native cottonwoods.

    Science.gov (United States)

    Meinhardt, Kelley A; Gehring, Catherine A

    2012-03-01

    The disruption of mutualisms between plants and mycorrhizal fungi is a potentially powerful mechanism by which invasives can negatively impact native species, yet our understanding of this mechanism's role in exotic species invasion is still in its infancy. Here, we provide several lines of evidence indicating that invasive tamarisk (Tamarix sp.) negatively affects native cottonwoods (Populus fremontii) by disrupting their associations with arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) fungi. At a field site in the early stages of tamarisk invasion, cottonwoods with tamarisk neighbors had reduced EM colonization and altered EM fungal community composition relative to cottonwoods with native neighbors, leading to reductions in EM propagule abundance in the soil beneath tamarisk. Similarly, AM colonization of cottonwoods was reduced with a tamarisk neighbor, but there were no significant changes in AM fungal spore communities or propagule abundance. Root colonization by nonmycorrhizal fungi, including potential pathogens, was higher in cottonwoods with tamarisk neighbors. A greenhouse experiment in which AM and EM inoculation and plant neighbor were manipulated in a fully factorial design showed that cottonwoods benefited from mycorrhizas, especially EM, in terms of shoot biomass when grown with a conspecific, but shoot biomass was similar to that of nonmycorrhizal controls when cottonwoods were grown with a tamarisk neighbor. These results are partially explained by a reduction in EM but not AM colonization of cottonwoods by a tamarisk neighbor. Tamarisk neighbors negatively affected cottonwood specific leaf area, but not chlorophyll content, in the field. To pinpoint a mechanism for these changes, we measured soil chemistry in the field and the growth response of an EM fungus (Hebeloma crustuliniforme) to salt-amended media in the laboratory. Tamarisk increased both NO3- concentrations and electrical conductivity 2.5-fold beneath neighboring cottonwoods in

  2. Effects of hydrology on red mangrove recruits

    Science.gov (United States)

    Doyle, Thomas W.

    2003-01-01

    Coastal wetlands along the Gulf of Mexico have been experiencing significant shifts in hydrology and salinity levels over the past century as a result of changes in sea level and freshwater drainage patterns. Local land management in coastal zones has also impacted the hydrologic regimes of salt marshes and mangrove areas. Parks and refuges in south Florida that contain mangrove forests have, in some cases, been ditched or impounded to control mosquito outbreaks and to foster wildlife use. And while mangroves dominate the subtropical coastlines of Florida and thrive in saltwater environments, little is known about how they respond to changes in hydrology under managed or variable tidal conditions. USGS researchers designed a study to evaluate the basic hydrological requirements of mangroves so that their health and survival may be more effectively managed in controlled impoundments and restored wetlands. Mangroves are commonly found in the intertidal zone (between low and high tides) in a rather broad spectrum of hydrologic settings. Because they thrive at the interface of land and sea, mangroves are subject to changes in freshwater flow (flow rate, nutrients, pollutants) and to marine influences (sea-level rise, salinity). Salinity has long been recognized as a controlling factor that determines the health and distribution of mangrove forests. Field and experimental observations indicate that most mangrove species achieve their highest growth potential under brackish conditions (modest salinity) between 10 and 20 parts per thousand (ppt). Yet, if provided with available propagules, successful regeneration, and limited competition from other plants, then mangroves can survive and thrive in freshwater systems as well. Because little is known about the growthand survival patterns of mangrove species relative to changing hydrology, USGS scientists conducted greenhouse and field experiments to determine how flooded or drained patterns of hydrology would influence

  3. Diversidade de fungos micorrízicos arbusculares em área de Caatinga, PE, Brasil Diversity of arbuscular mycorrizal fungi in an area of Caatinga, PE, Brazil

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    Catarina Maria Aragão de Mello

    2012-12-01

    Full Text Available O objetivo deste trabalho foi o de determinar a infectividade, a riqueza de FMA e a condição micorrízica da vegetação em área de Caatinga não antropizada. Coleta de solo e raízes foi realizada em Triunfo/PE. Raízes foram examinadas para determinação da colonização micorrízica. O número mais provável (NMP de propágulos infectivos de FMA foi estimado por diluições sucessivas do solo e a utilização de milho (Zea mays L. como planta isca. Glomerosporos foram quantificados e preparados em lâminas, para identificação das espécies. As plantas apresentaram-se pouco colonizadas (média The objective of this work was to determine the infectivity and richness of AMF and the mycorrhizal conditions of the vegetation in a preserved area of Caatinga. Soil and root samples were taken in two subareas in the municipality of Triunfo, PE. The roots were stained with Trypan blue, and observed with a microscope to determine if colonization of mycorrhizal fungi was present. Glomerospores were extracted from soil, counted, mounted on microscope slides and the AMF species were identified. The plants from the area showed < 10% colonization. The number of glomerospores (<1 g-1 soil did not differ between the subareas although in one area the amount of P in the soil was three times higher than in the other. The number of AMF propagules varied from 64 to 70 cm-3 in the soil. Sixteen taxa of AMF were registered and Glomus was the most representative genus, with seven species. Pacispora boliviana is reported for the first time in Brazil. The high amount of P probably contributes to the low values of propagules, colonization, infectivity and richness of AMF in the area. AMF have been commonly found in the Brazilian semiarid region and species of Glomus are predominant in this environment.

  4. Dinoflagellate blooms in upwelling systems: Seeding, variability, and contrasts with diatom bloom behaviour

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    Smayda, T. J.; Trainer, V. L.

    2010-04-01

    The influence of diatom bloom behaviour, dinoflagellate life cycles, propagule type and upwelling bloom cycles on the seeding of dinoflagellate blooms in eastern boundary current upwelling systems is evaluated. Winter-spring diatom bloom behaviour is contrasted with upwelling bloom behaviour because their phenology impacts dinoflagellate blooms. The winter-spring diatom bloom is usually sustained, whereas the classical upwelling diatom bloom occurs as a series of separate, recurrent mini-blooms intercalated by upwelling-relaxation periods, during which dinoflagellates often bloom. Four sequential wind-regulated phases characterize upwelling cycles, with each phase having different effects on diatom and dinoflagellate bloom behaviour: bloom “spin up”, bloom maximum, bloom “spin down”, and upwelling relaxation. The spin up - bloom maximum is the period of heightened diatom growth; the spin down - upwelling-relaxation phases are the periods when dinoflagellates often bloom. The duration, intensity and ratio of the upwelling and relaxation periods making up upwelling cycles determine the potential for dinoflagellate blooms to develop within a given upwelling cycle and prior to the subsequent “spin up” of upwelling that favours diatom blooms. Upwelling diatoms and meroplanktonic dinoflagellates have three types of propagules available to seed blooms: vegetative cells, resting cells and resting cysts. However, most upwelling dinoflagellates are holoplanktonic, which indicates that the capacity to form resting cysts is not an absolute requirement for growth and survival in upwelling systems. The long-term (decadal) gaps in bloom behaviour of Gymnodinium catenatum and Lingulodinium polyedrum, and the unpredictable bloom behaviour of dinoflagellates generally, are examined from the perspective of seeding strategies. Mismatches between observed and expected in situ bloom behaviour and resting cyst dynamics are common among upwelling dinoflagellates. This

  5. Fontes de silício no desenvolvimento de plântulas de bananeira 'Maçã' micropropagadas Sources of silicon in the development of micropropagated seedlings of banana 'Maçã'

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    Simone Abreu Asmar

    2011-07-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito de diferentes fontes de silício durante a fase de enraizamento in vitro de bananeira 'Maçã' por meio de análise fisiológica, fitotécnica e ultraestrutural. Foram utilizados propágulos já estabelecidos in vitro e inoculados em meio MURASHIGE & SKOOG (MS, adicionado de 30g L-1 de sacarose, 1mg L-1 de ANA (ácido naftalenoacético e solidificado com 1,8g L-1 de PhytagelTM. Foram testadas três fontes de silicato acrescidas ao meio MS, silicato de sódio, silicato de potássio e silicato de cálcio, na dosagem de 1g L-1 e o meio MS sem silicato como testemunha. O delineamento experimental foi o inteiramente casualizado, com quinze repetições. Os propágulos foram mantidos por 45 dias em sala de crescimento, sob condições controladas. Verificou-se aumento nos teores de clorofila a, b e total na presença de silicato de cálcio. A suplementação do meio de cultura com silicato de sódio promoveu aumento de comprimento, massa fresca e seca de parte aérea. O silício proporciona adequado desenvolvimento das plântulas.The objective of the research was to evaluate the effect of different sources of silicon during the in vitro rooting phase of 'Maçã' banana tree by means of physiological, phytotechnical and ultrastructural analysis. It was used propagules already established in vitro which were inoculated in MURASHIGE & SKOOG (MS medium, added of 30g L-1 of sucrose, 1mg L-1 of NAA (naphthalene acetic acid and solidified with 1.8g L-1 of PhytagelTM. It was tested three sources of silicate added to MS medium, sodium silicate, potassium silicate and calcium silicate, at a dose of 1g L-1 and MS medium without silicate as a witness. The experimental design was completely randomized with fifteen replicates. The propagules were kept for 45 days in a growth room under controlled conditions. There was an increase in levels of chlorophyll a, b and total in the presence of calcium silicate

  6. Apparent Contradiction: Psychrotolerant Bacteria from Hydrocarbon-Contaminated Arctic Tundra Soils That Degrade Diterpenoids Synthesized by Trees

    Science.gov (United States)

    Yu, Zhongtang; Stewart, Gordon R.; Mohn, William W.

    2000-01-01

    Resin acids are tricyclic terpenoids occurring naturally in trees. We investigated the occurrence of resin acid-degrading bacteria on the Arctic tundra near the northern coast of Ellesmere Island (82°N, 62°W). According to most-probable-number assays, resin acid degraders were abundant (103 to 104 propagules/g of soil) in hydrocarbon-contaminated soils, but they were undetectable (soil) in pristine soils from the nearby tundra. Plate counts indicated that the contaminated and the pristine soils had similar populations of heterotrophs (106 to 107 propagules/g of soil). Eleven resin acid-degrading bacteria belonging to four phylogenetically distinct groups were enriched and isolated from the contaminated soils, and representative isolates of each group were further characterized. Strains DhA-91, IpA-92, and IpA-93 are members of the genus Pseudomonas. Strain DhA-95 is a member of the genus Sphingomonas. All four strains are psychrotolerant, with growth temperature ranges of 4°C to 30°C (DhA-91 and DhA-95) or 4°C to 22°C (IpA-92 and IpA-93) and with optimum temperatures of 15 to 22°C. Strains DhA-91 and DhA-95 grew on the abietanes, dehydroabietic and abietic acids, but not on the pimaranes, isopimaric and pimaric acids. Strains IpA-92 and IpA-93 grew on the pimaranes but not the abietanes. All four strains grew on either aliphatic or aromatic hydrocarbons, which is unusual for described resin acid degraders. Eleven mesophilic resin acid degraders did not use hydrocarbons, with the exception of two Mycobacterium sp. strains that used aliphatic hydrocarbons. We conclude that hydrocarbon contamination in Arctic tundra soil indirectly selected for resin acid degraders, selecting for hydrocarbon degraders that coincidentally use resin acids. Psychrotolerant resin acid degraders are likely important in the global carbon cycle and may have applications in biotreatment of pulp and paper mill effluents. PMID:11097882

  7. Endophytic fungi from the roots of horseradish (Armoracia rusticana) and their interactions with the defensive metabolites of the glucosinolate - myrosinase - isothiocyanate system.

    Science.gov (United States)

    Szűcs, Zsolt; Plaszkó, Tamás; Cziáky, Zoltán; Kiss-Szikszai, Attila; Emri, Tamás; Bertóti, Regina; Sinka, László Tamás; Vasas, Gábor; Gonda, Sándor

    2018-05-09

    The health of plants is heavily influenced by the intensively researched plant microbiome. The microbiome has to cope with the plant's defensive secondary metabolites to survive and develop, but studies that describe this interaction are rare. In the current study, we describe interactions of endophytic fungi with a widely researched chemical defense system, the glucosinolate - myrosinase - isothiocyanate system. The antifungal isothiocyanates are also of special interest because of their beneficial effects on human consumers. Seven endophytic fungi were isolated from horseradish roots (Armoracia rusticana), from the genera Fusarium, Macrophomina, Setophoma, Paraphoma and Oidiodendron. LC-ESI-MS analysis of the horseradish extract incubated with these fungi showed that six of seven strains could decompose different classes of glucosinolates. Aliphatic, aromatic, thiomethylalkyl and indolic glucosinolates were decomposed by different strains at different rates. SPME-GC-MS measurements showed that two strains released significant amounts of allyl isothiocyanate into the surrounding air, but allyl nitrile was not detected. The LC-ESI-MS analysis of many strains' media showed the presence of allyl isothiocyanate - glutathione conjugate during the decomposition of sinigrin. Four endophytic strains also accepted sinigrin as the sole carbon source. Isothiocyanates inhibited the growth of fungi at various concentrations, phenylethyl isothiocyanate was more potent than allyl isothiocyanate (mean IC 50 was 2.30-fold lower). As a control group, ten soil fungi from the same soil were used. They decomposed glucosinolates with lower overall efficiency: six of ten strains had insignificant or weak activities and only three could use sinigrin as a carbon source. The soil fungi also showed lower AITC tolerance in the growth inhibition assay: the median IC 50 values were 0.1925 mM for endophytes and 0.0899 mM for soil fungi. The host's glucosinolates can be used by the tested

  8. Ocorrência e sintomas da mancha de Ascochyta em feijão-vagem Occurrence and symptoms of Ascochyta blight on snap bean

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    Maria Aparecida de Souza Tanaka

    1996-01-01

    , cultural and morphological characteristics of the fungus, besides pathogenicity tests. The disease was confused with Alternaria blight, on the leaves, or Macrophomina rot, on the lower part of stems. The pathogen identification permitted to avoid misidentification and to establish measures of control.

  9. Multistate models of bigheaded carps in the Illinois River reveal spatial dynamics of invasive species

    Science.gov (United States)

    Coulter, Alison A.; Brey, Marybeth; Lubejko, Matthew; Kallis, Jahn L.; Coulter, David P.; Glover, David C.; Whitledge, Gregory W.; Garvey, James E.

    2018-01-01

    Knowledge of the spatial distributions and dispersal characteristics of invasive species is necessary for managing the spread of highly mobile species, such as invasive bigheaded carps (Bighead Carp [Hypophthalmichthys nobilis] and Silver Carp [H. molitrix]). Management of invasive bigheaded carps in the Illinois River has focused on using human-made barriers and harvest to limit dispersal towards the Laurentian Great Lakes. Acoustic telemetry data were used to parameterize multistate models to examine the spatial dynamics of bigheaded carps in the Illinois River to (1) evaluate the effects of existing dams on movement, (2) identify how individuals distribute among pools, and (3) gauge the effects of reductions in movement towards the invasion front. Multistate models estimated that movement was generally less likely among upper river pools (Starved Rock, Marseilles, and Dresden Island) than the lower river (La Grange and Peoria) which matched the pattern of gated versus wicket style dams. Simulations using estimated movement probabilities indicated that Bighead Carp accumulate in La Grange Pool while Silver Carp accumulate in Alton Pool. Fewer Bighead Carp reached the upper river compared to Silver Carp during simulations. Reducing upstream movement probabilities (e.g., reduced propagule pressure) by ≥ 75% into any of the upper river pools could reduce upper river abundance with similar results regardless of location. Given bigheaded carp reproduction in the upper Illinois River is presently limited, reduced movement towards the invasion front coupled with removal of individuals reaching these areas could limit potential future dispersal towards the Great Lakes.

  10. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan

    International Nuclear Information System (INIS)

    Zellmer, S.D.; Rastorfer, J.R.; Van Dyke, G.D.

    1991-07-01

    Implementation of recent federal and state regulations promulgated to protect wetlands makes information on effects of gas pipeline rights-of-way (ROWs) in wetlands essential to the gas pipeline industry. This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth forested wetland sites mapped as Lenawee soils, one mature and one subjected to recent selective logging, were selected in Midland County, Michigan. Changes in the adjacent forest and successional development on the ROW are being documented. Cover-class estimates are being made for understory and ROW plant species using 1 x1-m quadrats. Counts are also being made for all woody species with stems < 2 cm in diameter at breast height (dbh) in the same plots used for cover-class estimates. Individual stem diameters and species counts are being recorded for all woody understory and overstory plants with stems ≥2 cm dbh in 10 x 10-m plots. Although analyses of the data have not been completed, preliminary analyses indicate that some destruction of vegetation at the ROW forest edge may have been avoidable during pipeline construction. Rapid regrowth of many native wetland plant species on the ROW occurred because remnants of native vegetation and soil-bearing propagules of existing species survived on the ROW after pipeline construction and seeding operations. 91 refs., 11 figs., 3 tabs

  11. Microbial Inoculantes Effects on Growth Promotion of Mangrove and Citrullus vulgaris San Andrés Isla, Colombia

    Directory of Open Access Journals (Sweden)

    Tania Galindo

    2006-01-01

    Full Text Available In order to test the effect of two microbial inoculants (obtained from red and black mangrove roots on the growth and stability of mangrove and watermelon plants, four treatments were carried out in San Andres Island, Colombia. The treatments consisted in the application of the inoculants in: A. germinans propagules collected in a mangrove area, and then individually planted in gavels with sun-pasteurized soil (in order to decrease the microbial load, A. germinans and R. mangle plants collected in the proximity of nursery trees, A. germinans and R. mangle planted and maintained in nursery, and in Citrullus vulgaris seeds planted in a traditional cultivar without chemical fertilizers. The growth and vegetative development variables were: number of nodes, number of leaves and steam length. The inoculants (phosphate solubilizing microorganisms -PSM- and nitrogen fixing bacteria -NFB- were applied in the mentioned vegetable material, doing measures during three months. The results show a positive effect on growth measured by steam length in plants treated specifically with the inoculants in C. vulgaris and A. germinans seedlings maintained in nursery.

  12. Two new fern chloroplasts and decelerated evolution linked to the long generation time in tree ferns.

    Science.gov (United States)

    Zhong, Bojian; Fong, Richard; Collins, Lesley J; McLenachan, Patricia A; Penny, David

    2014-04-30

    We report the chloroplast genomes of a tree fern (Dicksonia squarrosa) and a "fern ally" (Tmesipteris elongata), and show that the phylogeny of early land plants is basically as expected, and the estimates of divergence time are largely unaffected after removing the fastest evolving sites. The tree fern shows the major reduction in the rate of evolution, and there has been a major slowdown in the rate of mutation in both families of tree ferns. We suggest that this is related to a generation time effect; if there is a long time period between generations, then this is probably incompatible with a high mutation rate because otherwise nearly every propagule would probably have several lethal mutations. This effect will be especially strong in organisms that have large numbers of cell divisions between generations. This shows the necessity of going beyond phylogeny and integrating its study with other properties of organisms. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  13. Microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants in lead contaminated soil

    Directory of Open Access Journals (Sweden)

    Graziella S Gattai

    2011-09-01

    Full Text Available The goals of this study were to evaluate the microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants (Caesalpinia ferrea, Mimosa tenuiflora and Erythrina velutina in lead contaminated soil from the semi-arid region of northeastern of Brazil (Belo Jardim, Pernambuco. Dilutions were prepared by adding lead contaminated soil (270 mg Kg-1 to uncontaminated soil (37 mg Pb Kg soil-1 in the proportions of 7.5%, 15%, and 30% (v:v. The increase of lead contamination in the soil negatively influenced the amount of carbon in the microbial biomass of the samples from both the dry and rainy seasons and the metabolic quotient only differed between the collection seasons in the 30% contaminated soil. The average value of the acid phosphatase activity in the dry season was 2.3 times higher than observed during the rainy season. There was no significant difference in the number of glomerospores observed between soils and periods studied. The most probable number of infective propagules was reduced for both seasons due to the excess lead in soil. The mycorrhizal colonization rate was reduced for the three plant species assayed. The inoculation with arbuscular mycorrhizal fungi benefited the growth of Erythrina velutina in lead contaminated soil.

  14. Monitoring benthic foraminiferal dynamics at Bottsand coastal lagoon (western Baltic Sea)

    Science.gov (United States)

    Schönfeld, Joachim

    2018-04-01

    Benthic foraminifera from Bottsand coastal lagoon, western Baltic Sea, have been studied since the mid-1960s. They were monitored annually in late autumn since 2003 at the terminal ditch of the lagoon. There were 12 different species recognised, of which three have not been recorded during earlier investigations. Dominant species showed strong interannual fluctuations and a steady increase in population densities over the last decade. Elphidium incertum, a stenohaline species of the Baltic deep water fauna, colonised the Bottsand lagoon in 2016, most likely during a period of salinities >19 units and water temperatures of 18 °C on average in early autumn. The high salinities probably triggered their germination from a propagule bank in the ditch bottom sediment. The new E. incertum population showed densities higher by an order of magnitude than those of the indigenous species. The latter did not decline, revealing that E. incertum used another food source or occupied a different microhabitat. Elphidium incertum survived transient periods of lower salinities in late autumn 2017, though with reduced abundances, and became a regular faunal constituent at the Bottsand lagoon.

  15. Mangrove Crab Ucides cordatus Removal Does Not Affect Sediment Parameters and Stipule Production in a One Year Experiment in Northern Brazil

    Science.gov (United States)

    2016-01-01

    Mangrove crabs influence ecosystem processes through bioturbation and/or litter feeding. In Brazilian mangroves, the abundant and commercially important crab Ucides cordatus is the main faunal modifier of microtopography establishing up to 2 m deep burrows. They process more than 70% of the leaf litter and propagule production, thus promoting microbial degradation of detritus and benefiting microbe-feeding fiddler crabs. The accelerated nutrient turn-over and increased sediment oxygenation mediated by U. cordatus may enhance mangrove tree growth. Such positive feed-back loop was tested in North Brazil through a one year crab removal experiment simulating increased harvesting rates in a mature Rhizophora mangle forest. Investigated response parameters were sediment salinity, organic matter content, CO2 efflux rates of the surface sediment, and reduction potential. We also determined stipule fall of the mangrove tree R. mangle as a proxy for tree growth. Three treatments were applied to twelve experimental plots (13 m × 13 m each): crab removal, disturbance control and control. Within one year, the number of U. cordatus burrows inside the four removal plots decreased on average to 52% of the initial number. Despite this distinct reduction in burrow density of this large bioturbator, none of the measured parameters differed between treatments. Instead, most parameters were clearly influenced by seasonal changes in precipitation. Hence, in the studied R. mangle forest, abiotic factors seem to be more important drivers of ecosystem processes than factors mediated by U. cordatus, at least within the studied timespan of one year. PMID:27907093

  16. Land crabs as key drivers in tropical coastal forest recruitment

    Science.gov (United States)

    Lindquist, E.S.; Krauss, K.W.; Green, P.T.; O'Dowd, D. J.; Sherman, P.M.; Smith, T. J.

    2009-01-01

    Plant populations are regulated by a diverse assortment of abiotic and biotic factors that influence seed dispersal and viability, and seedling establishment and growth at the microsite. Rarely does one animal guild exert as significant an influence on different plant assemblages as land crabs. We review three tropical coastal ecosystems-mangroves, island maritime forests, and mainland coastal terrestrial forests-where land crabs directly influence forest composition by limiting tree establishment and recruitment. Land crabs differentially prey on seeds, propagules and seedlings along nutrient, chemical and physical environmental gradients. In all of these ecosystems, but especially mangroves, abiotic gradients are well studied, strong and influence plant species distributions. However, we suggest that crab predation has primacy over many of these environmental factors by acting as the first limiting factor of tropical tree recruitment to drive the potential structural and compositional organisation of coastal forests. We show that the influence of crabs varies relative to tidal gradient, shoreline distance, canopy position, time, season, tree species and fruiting periodicity. Crabs also facilitate forest growth and development through such activities as excavation of burrows, creation of soil mounds, aeration of soils, removal of leaf litter into burrows and creation of carbon-rich soil microhabitats. For all three systems, land crabs influence the distribution, density and size-class structure of tree populations. Indeed, crabs are among the major drivers of tree recruitment in tropical coastal forest ecosystems, and their conservation should be included in management plans of these forests. ?? 2009 Cambridge Philosophical Society.

  17. Shoot cuttings propagation of giant reed (Arundo donax L.) in water and moist soil: The path forward?

    Energy Technology Data Exchange (ETDEWEB)

    Ceotto, Enrico; Di Candilo, Mario [C.R.A. - Centro di Ricerca per le Colture Industriali, Via di Corticella 133, 40128 Bologna (Italy)

    2010-11-15

    Giant reed (Arundo donax L.) is a perennial rhizomatous grass that can be regarded as an ideal crop for bioenergy production, owing to several intrinsic characteristics. Despite to the promising yield results obtained in many plot experiments, the cultivation of giant reed at field scale is still a challenge. Owing to the floral sterility of the species, rhizome propagation has been predominantly used to establish field plots experiments, although this method is unpractical and monetarily expensive. Giant reed is a hydrophytic plant that typically spread in riparian systems by flood-mediated fragmentation and dispersal of vegetative propagules. Since giant reed propagation is strictly dependent on temporary abundance of water, this plant characteristic might be exploited for fostering the diffusion of giant reed as a bioenergy field crop. The objectives of this paper were: i) to disseminate some techniques for shoot cutting propagation of giant reed in water and in moist soil; ii) to address the critical points that remain to be solved for a widespread diffusion of this species as a bioenergy field crop. (author)

  18. Zostera marina (eelgrass) growth and survival along a gradient ofnutrients and turbidity in the lower Chesapeake Bay

    Science.gov (United States)

    Moore, K.A.; Neckles, H.A.; Orth, R.J.

    1996-01-01

    Survival of transplanted Zostera marina L. (eelgrass), Z. marina growth,and environmental conditions were studied concurrently at a number of sitesin a southwestern tributary of the Chesapeake Bay to elucidate the factorslimiting macrophyte distribution in this region. Consistent differences insurvival of the transplants were observed, with no long-term survival at anyof the sites that were formerly vegetated with this species but thatcurrently remain unvegetated. Therefore, the current distribution of Z.marina likely represents the extent of suitable environmental conditions inthe region, and the lack of recovery into historically vegetated sites is notsolely due to lack of propagules. Poor long-term survival was related toseasonally high levels of water column light attenuation. Fall transplantsdied by the end of summer following exposure to levels of high springturbidity (K(d) > 3.0). Accumulation of an epiphyte matrix during the latespring (0.36 to 1.14 g g-1 dry wt) may also have contributed to thisstress. Differences in water column nutrient levels among sites during thefall and winter (10 to 15 ??M dissolved inorganic nitrogen and 1 ??Mdissolved inorganic phosphates) had no observable effect on epiphyteaccumulation or macrophyte growth. Salinity effects were minor and there wereno symptoms of disease. Although summertime conditions resulted indepressions in growth, they did not alone limit long-term survival. It issuggested that water quality conditions enhancing adequate seagrass growthduring the spring may be key to long-term Z. marina survival and successfulrecolonization in this region.

  19. Neutral lipid fatty acid analysis is a sensitive marker for quantitative estimation of arbuscular mycorrhizal fungi in agricultural soil with crops of different mycotrophy

    Directory of Open Access Journals (Sweden)

    Mauritz Vestberg

    2012-03-01

    Full Text Available The impact of host mycotrophy on arbuscular mycorrhizal fungal (AMF markers was studied in a temperate agricultural soil cropped with mycorrhizal barley, flax, reed canary-grass, timothy, caraway and quinoa and non-mycorrhizal buckwheat, dyer's woad, nettle and false flax. The percentage of AMF root colonization, the numbers of infective propagules by the Most Probable Number (MPN method, and the amounts of signature Phospholipid Fatty Acid (PLFA 16:1ω5 and Neutral Lipid Fatty Acid (NLFA 16:1ω5 were measured as AMF markers.  Crop had a significant impact on MPN levels of AMF, on NLFA 16:1ω5 levels in bulk and rhizosphere soil and on PLFA 16:1ω5 levels in rhizosphere soil. Reed canary-grass induced the highest levels of AMF markers. Mycorrhizal markers were at low levels in all non-mycorrhizal crops. NLFA 16:1ω5 and the ratio of NLFA to PLFA 16:1ω5 from bulk soil are adequate methods as indicators of AMF biomass in soil.

  20. Use of perches and seed dispersal by birds in an abandoned pasture in the Porto Ferreira state park, southeastern Brazil

    Directory of Open Access Journals (Sweden)

    S. Athiê

    Full Text Available Abstract We investigated the efficiency of different kinds of perches in attracting seed disperser-birds and increasing the seed rain in a degraded area located in the northeast region of São Paulo State. We installed seed traps under natural perches (NPs, living trees; simple artificial perches (SAPs of 3m tall and a crossbar; elaborate artificial perches (EAPs of 7m tall and three crossbars, and in a control area. Results showed the number of bird-dispersed seeds deposited was proportional to the number of structures for perching. The NPs also have provided other resources for birds such as food and shelter. Comparing visitation between artificial perches, there was greater use of EAPs also for having more perching structures and for being taller, providing better airspace visibility for predatory birds and tyrant-flycatchers, important seed dispersers. Thus, natural and artificial perches with similar characteristics to the EAPs are the most recommended as a base or complementary method for the restoration of degraded areas near to propagules source, also contributing to the maintenance of local fauna.

  1. Between a Pod and a Hard Test: The Deep Evolution of Amoebae.

    Science.gov (United States)

    Kang, Seungho; Tice, Alexander K; Spiegel, Frederick W; Silberman, Jeffrey D; Pánek, Tomáš; Cepicka, Ivan; Kostka, Martin; Kosakyan, Anush; Alcântara, Daniel M C; Roger, Andrew J; Shadwick, Lora L; Smirnov, Alexey; Kudryavtsev, Alexander; Lahr, Daniel J G; Brown, Matthew W

    2017-09-01

    Amoebozoa is the eukaryotic supergroup sister to Obazoa, the lineage that contains the animals and Fungi, as well as their protistan relatives, and the breviate and apusomonad flagellates. Amoebozoa is extraordinarily diverse, encompassing important model organisms and significant pathogens. Although amoebozoans are integral to global nutrient cycles and present in nearly all environments, they remain vastly understudied. We present a robust phylogeny of Amoebozoa based on broad representative set of taxa in a phylogenomic framework (325 genes). By sampling 61 taxa using culture-based and single-cell transcriptomics, our analyses show two major clades of Amoebozoa, Discosea, and Tevosa. This phylogeny refutes previous studies in major respects. Our results support the hypothesis that the last common ancestor of Amoebozoa was sexual and flagellated, it also may have had the ability to disperse propagules from a sporocarp-type fruiting body. Overall, the main macroevolutionary patterns in Amoebozoa appear to result from the parallel losses of homologous characters of a multiphase life cycle that included flagella, sex, and sporocarps rather than independent acquisition of convergent features. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  2. Critical factors in the establishment of allopolyploids.

    Science.gov (United States)

    Fowler, Norma L; Levin, Donald A

    2016-07-01

    The growth and spread of new polyploid populations have been explained in terms of fitness advantages over their diploid progenitors. However, a fitness advantage is not sufficient to insure the establishment of a polyploid; it must also overcome the obstacles of demographic stochasticity and minority disadvantage. Several studies have addressed the population dynamics of autopolyploids, but the present study is the first to consider allopolyploids, which are affected by more factors than autopolyploids. We constructed a population dynamic model of four types of plants (two parent species, hybrids, allopolyploids) that also included an explicit breeding system. The numbers of plants of each type were the most important factors determining whether the new allopolyploid would become established. More polyploid plants greatly increased the likelihood of polyploid persistence. More plants of the parent species and more hybrids resulted in more polyploids being produced. The model parameters with the most effect on polyploid establishment were potential population size (K), individual plant fecundity, and niche separation (α). The most important breeding system parameters were selfing rates, which mitigated minority disadvantage imposed by pollen limitation. The importance of population sizes, and the parameters that controlled them, in overcoming demographic stochasticity parallels the well-recognized role of propagule pressure in determining the success of invasive species. We modeled the establishment of a new allopolyploid; analogous considerations would affect the establishment of a new autopolyploid. The critical role of population sizes in polyploid establishment should be more widely recognized. © 2016 Botanical Society of America.

  3. Ancestral origins and invasion pathways in a globally invasive bird correlate with climate and influences from bird trade.

    Science.gov (United States)

    Jackson, Hazel; Strubbe, Diederik; Tollington, Simon; Prys-Jones, Robert; Matthysen, Erik; Groombridge, Jim J

    2015-08-01

    Invasive species present a major threat to global biodiversity. Understanding genetic patterns and evolutionary processes that reinforce successful establishment is paramount for elucidating mechanisms underlying biological invasions. Among birds, the ring-necked parakeet (Psittacula krameri) is one of the most successful invasive species, established in over 35 countries. However, little is known about the evolutionary genetic origins of this species and what population genetic signatures tell us about patterns of invasion. We reveal the ancestral origins of populations across the invasive range and explore the potential influence of climate and propagule pressure from the pet trade on observed genetic patterns. Ring-necked parakeet samples representing the ancestral native range (n = 96) were collected from museum specimens, and modern samples from the invasive range (n = 855) were gathered from across Europe, Mauritius and Seychelles, and sequenced for two mitochondrial DNA markers comprising 868 bp of cytochrome b and control region, and genotyped at 10 microsatellite loci. Invasive populations comprise birds that originate predominantly from Pakistan and northern areas of India. Haplotypes associated with more northerly distribution limits in the ancestral native range were more prevalent in invasive populations in Europe, and the predominance of Asian haplotypes in Europe is consistent with the higher number of Asian birds transported by the pet trade outside the native range. Successful establishment of invasive species is likely to be underpinned by a combination of environmental and anthropogenic influences. © 2015 John Wiley & Sons Ltd.

  4. Genetic diversity in three invasive clonal aquatic species in New Zealand

    Directory of Open Access Journals (Sweden)

    Sorrell Brian K

    2010-06-01

    Full Text Available Abstract Background Elodea canadensis, Egeria densa and Lagarosiphon major are dioecious clonal species which are invasive in New Zealand and other regions. Unlike many other invasive species, the genetic variation in New Zealand is very limited. Clonal reproduction is often considered an evolutionary dead end, even though a certain amount of genetic divergence may arise due to somatic mutations. The successful growth and establishment of invasive clonal species may be explained not by adaptability but by pre-existing ecological traits that prove advantageous in the new environment. We studied the genetic diversity and population structure in the North Island of New Zealand using AFLPs and related the findings to the number of introductions and the evolution that has occurred in the introduced area. Results Low levels of genetic diversity were found in all three species and appeared to be due to highly homogeneous founding gene pools. Elodea canadensis was introduced in 1868, and its populations showed more genetic structure than those of the more recently introduced of E. densa (1946 and L. major (1950. Elodea canadensis and L. major, however, had similar phylogeographic patterns, in spite of the difference in time since introduction. Conclusions The presence of a certain level of geographically correlated genetic structure in the absence of sexual reproduction, and in spite of random human dispersal of vegetative propagules, can be reasonably attributed to post-dispersal somatic mutations. Direct evidence of such evolutionary events is, however, still insufficient.

  5. Environmental effects research. Environmental Research Division annual report, January-December 1983. Part 3

    International Nuclear Information System (INIS)

    1984-12-01

    The Terrestrial Ecology group continued its involvement in the National Crop Loss Assessment Network, and studies of O 3 effects on winter wheat and soybeans were completed. Experiments on O 3 x SO 2 interactions on soybeans were also performed. The Microcosms for Acid Rain Studies (MARS) project had its first full year of research and much information concerning acid rain impacts on soil-plant systems was collected. A study of the influence of temporal variations in rain acidity on soybean productivity was also initiated. The aquatic radiochemistry group continued measurements of the mobility of plutonium and americium at a disposal site at Los Alamos and initiated similar work at Hanford. Laboratory tracer experiments were carried out to study the adsorptive behavior of neptunium, the solubility limits of plutonium, and the influence of rare earth concentration on the sorption and redox behavior of plutonium. The soil-plant process group initiated several studies on the influence of mycorrhizae to host plants in disturbed and natural environments. Much of the past research has been concerned with understanding mycorrhizal fungi propagule dynamics as related to disturbances associated with energy extraction. Future research will be directed at understanding how below-ground symbiotic associations may increase the fitness of host plants. Emphasis is being placed on resource acquisition and compartmental strategies. Separate analytics have been indexed for EDB

  6. The role of adaptive trans-generational plasticity in biological invasions of plants.

    Science.gov (United States)

    Dyer, Andrew R; Brown, Cynthia S; Espeland, Erin K; McKay, John K; Meimberg, Harald; Rice, Kevin J

    2010-03-01

    High-impact biological invasions often involve establishment and spread in disturbed, high-resource patches followed by establishment and spread in biotically or abiotically stressful areas. Evolutionary change may be required for the second phase of invasion (establishment and spread in stressful areas) to occur. When species have low genetic diversity and short selection history, within-generation phenotypic plasticity is often cited as the mechanism through which spread across multiple habitat types can occur. We show that trans-generational plasticity (TGP) can result in pre-adapted progeny that exhibit traits associated with increased fitness both in high-resource patches and in stressful conditions. In the invasive sedge, Cyperus esculentus, maternal plants growing in nutrient-poor patches can place disproportional number of propagules into nutrient-rich patches. Using the invasive annual grass, Aegilops triuncialis, we show that maternal response to soil conditions can confer greater stress tolerance in seedlings in the form of greater photosynthetic efficiency. We also show TGP for a phenological shift in a low resource environment that results in greater stress tolerance in progeny. These lines of evidence suggest that the maternal environment can have profound effects on offspring success and that TGP may play a significant role in some plant invasions.

  7. Plant-microbe interactions: Plant hormone production by phylloplane fungi. Research report

    Energy Technology Data Exchange (ETDEWEB)

    Tuomi, T.; Ilvesoksa, J.; Rosenqvist, H.

    1993-06-23

    The molds Botrytis cinerea, Cladosporium cladosporioides and the yeast Aureobasidium pullulans, isolated from the leaves of three short-rotation Salix clones, were found to produce indole-3-acetic acid (a growth promoter of plants). Abscisic acid (a growth inhibitor of plants) production was detected in B. cinerea. The contents of indole-3-acetic acid and abscisic acid in the leaves of the Salix clones and the amounts of fungal propagules in these leaves were also measured, in order to evaluate whether the amounts of plant growth regulators produced by the fungi would make a significant contribution to the hormonal quantities of the leaves. The content of abscisic acid, and to a lesser degree that of indole-3-acetic acid, showed a positive correlation with the frequency of infection by the hormone producing organisms. The amounts of hormone producing fungi on leaves that bore visible colonies were, however, not sufficiently high to support the argument that neither the fungal production of abscisic nor indole-3-acetic acid would to a significant degree contribute to the hormonal contents of the leaves of the Salix clones.

  8. The first precinctive Carabidae from Moorea, Society Islands: new Mecyclothorax spp. (Coleoptera from the summit of Mont Tohiea

    Directory of Open Access Journals (Sweden)

    James Liebherr

    2012-09-01

    Full Text Available Seven species of Mecyclothorax Sharp from Moorea, Society Islands are newly described; M. perraulti sp. n., M. pahere sp. n., M. menemene sp. n., M. mahatahi sp. n., M. popotioaoa sp. n., M. mapo sp. n., and M. fatata sp. n. These constitute the first Mecyclothorax species described from Moorea, and the first carabid beetle species shown to be geographically restricted to that island. Each of the newly described species is most similar to a different species on the island of Tahiti, suggesting that none of the seven Moorean taxa are evolutionary end-products of autochthonous speciation within Moorea. The occurrence of precinctive Mecyclothorax species on both Moorea and Tahiti demonstrates that radiation of Mecyclothorax in the Society Islands has been facilitated by speciation events implicating both islands. Whether this speciation has been preceded by vicariance or dispersal is discussed, with the generality of a dispersal hypothesis tested using information from Society Island Nabidae (Hemiptera. Salient morphological characters for taxa in the Society and Hawaiian Islands are compared to those representing a broad survey of southwest Pacific Mecyclothorax spp. This comparison supports the independent founding of each radiation in the Societies and Hawaii from an Australian ancestral propagule, likely drawn from the ecologically general, geographically widespread M. punctipennis (Macleay.

  9. Molecular markers reveal infestation dynamics of the bed bug (Hemiptera: Cimicidae) within apartment buildings.

    Science.gov (United States)

    Booth, Warren; Saenz, Virna L; Santangelo, Richard G; Wang, Changlu; Schal, Coby; Vargo, Edward L

    2012-05-01

    The bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), has experienced an extraordinary global resurgence in recent years, the reasons for which remain poorly understood. Once considered a pest of lower socioeconomic classes, bed bugs are now found extensively across all residential settings, with widespread infestations established in multiapartment buildings. Within such buildings, understanding the population genetic structure and patterns of dispersal may prove critical to the development of effective control strategies. Here, we describe the development of 24 high-resolution microsatellite markers through next generation 454 pyrosequencing and their application to elucidate infestation dynamics within three multistory apartment buildings in the United States. Results reveal contrasting characteristics potentially representative of geographic or locale differences. In Raleigh, NC, an infestation within an apartment building seemed to have started from a single introduction followed by extensive spread. In Jersey City, NJ, two or more introductions followed by spread are evident in two buildings. Populations within single apartments in all buildings were characterized by high levels of relatedness and low levels of diversity, indicative of foundation from small, genetically depauperate propagules. Regardless of the number of unique introductions, genetic data indicate that spread within buildings is extensive, supporting both active and human-mediated dispersal within and between adjacent rooms or apartments spanning multiple floors.

  10. [Presumptive identification of Cryptococcus gattii isolated from Terminalia catappa in Montería city, Córdoba, Colombia].

    Science.gov (United States)

    Contreras Martínez, Orfa Inés; Aycardi Morinelli, María Paulina; Alarcón Furnieles, Jany Luz; Jaraba Ramos, Aparicio Manuel

    2011-01-01

    the members of the Cryptococcus neoformans species complex are responsible for cryptococcosis in animals and humans. Human infection is thought to be acquired by inhalation of airborne propagules from an environmental source; therefore it is greatly important to study their habitat. to determine the ecological relationship of Cryptococcus gattii with Terminalia catappa trees present in urban areas of Montería city in Colombia. a total of 163 Terminalia catappa trees were selected; some samples were taken from the bark, the leaves, the flowers, the fruits of these trees and from the surrounding soil. The yeast was isolated using the Guizotia abyssinica seed agar medium; it was identified thanks to biochemical and morphologic tests whereas the right variety was determined by L-canavanine-glycine-bromothymol blue (CGB), D-proline and D-tryptophan tests. there was obtained 9.050 CFU/g isolate of Cryptococcus spp., 5.795 CFU/g of which were presumptively identified as Cryptococcus gattii. The highest percentage of isolates was found in flowers, followed by bark and fruits, presenting small cellular and capsular sizes. These isolates were more frequent in the south of the city, followed by the center zone and the lowest percentage in the northern zone. these findings confirmed the close relationship of Cryptococcus gattii and Terminalia catappa, being this the first study conducted in Monteria city. These results give us meaningful information for understanding and analyzing the epidemiology of cryptococcosis in Monteria city, Colombia.

  11. Phenology and Growth dynamics of Avicennia marina in the Central Red Sea

    Science.gov (United States)

    Almahasheer, Hanan; Duarte, Carlos M.; Irigoien, Xabier

    2016-01-01

    The formation of nodes, stem elongation and the phenology of stunted Avicennia marina was examined in the Central Red Sea, where Avicennia marina is at the limit of its distribution range and submitted to extremely arid conditions with salinity above 38 psu and water temperature as high as 35° C. The annual node production was rather uniform among locations averaging 9.59 node y−1, which resulted in a plastocron interval, the interval in between production of two consecutive nodes along a stem, of 38 days. However, the internodal length varied significantly between locations, resulting in growth differences possibly reflecting the environmental conditions of locations. The reproductive cycle lasted for approximately 12 months, and was characterized by peak flowering and propagule development in November and January. These phenological observations provide a starting point for research and restoration programs on the ecology of mangroves in the Central Red Sea, while the plastochrone index reported here would allow calculations of the growth and production of the species from simple morphological measurements. PMID:27892956

  12. Predators and patterns of within-host growth can mediate both among-host competition and evolution of transmission potential of parasites.

    Science.gov (United States)

    Auld, Stuart K J R; Hall, Spencer R; Housley Ochs, Jessica; Sebastian, Mathew; Duffy, Meghan A

    2014-08-01

    Parasite prevalence shows tremendous spatiotemporal variation. Theory indicates that this variation might stem from life-history characteristics of parasites and key ecological factors. Here, we illustrate how the interaction of an important predator and the schedule of transmission potential of two parasites can explain parasite abundance. A field survey showed that a noncastrating fungus (Metschnikowia bicuspidata) commonly infected a dominant zooplankton host (Daphnia dentifera), while a castrating bacterial parasite (Pasteuria ramosa) was rare. This result seemed surprising given that the bacterium produces many more infectious propagules (spores) than the fungus upon host death. The fungus's dominance can be explained by the schedule of within-host growth of parasites (i.e., how transmission potential changes over the course of infection) and the release of spores from "sloppy" predators (Chaoborus spp., who consume Daphnia prey whole and then later regurgitate the carapace and parasite spores). In essence, sloppy predators create a niche that the faster-schedule fungus currently occupies. However, a selection experiment showed that the slower-schedule bacterium can evolve into this faster-schedule, predator-mediated niche (but pays a cost in maximal spore yield to do so). Hence, our study shows how parasite life history can interact with predation to strongly influence the ecology, epidemiology, and evolution of infectious disease.

  13. From ratites to rats: the size of fleshy fruits shapes species' distributions and continental rainforest assembly.

    Science.gov (United States)

    Rossetto, Maurizio; Kooyman, Robert; Yap, Jia-Yee S; Laffan, Shawn W

    2015-12-07

    Seed dispersal is a key process in plant spatial dynamics. However, consistently applicable generalizations about dispersal across scales are mostly absent because of the constraints on measuring propagule dispersal distances for many species. Here, we focus on fleshy-fruited taxa, specifically taxa with large fleshy fruits and their dispersers across an entire continental rainforest biome. We compare species-level results of whole-chloroplast DNA analyses in sister taxa with large and small fruits, to regional plot-based samples (310 plots), and whole-continent patterns for the distribution of woody species with either large (more than 30 mm) or smaller fleshy fruits (1093 taxa). The pairwise genomic comparison found higher genetic distances between populations and between regions in the large-fruited species (Endiandra globosa), but higher overall diversity within the small-fruited species (Endiandra discolor). Floristic comparisons among plots confirmed lower numbers of large-fruited species in areas where more extreme rainforest contraction occurred, and re-colonization by small-fruited species readily dispersed by the available fauna. Species' distribution patterns showed that larger-fruited species had smaller geographical ranges than smaller-fruited species and locations with stable refugia (and high endemism) aligned with concentrations of large fleshy-fruited taxa, making them a potentially valuable conservation-planning indicator. © 2015 The Author(s).

  14. The Halogenated Metabolism of Brown Algae (Phaeophyta, Its Biological Importance and Its Environmental Significance

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    Stéphane La Barre

    2010-03-01

    Full Text Available Brown algae represent a major component of littoral and sublittoral zones in temperate and subtropical ecosystems. An essential adaptive feature of this independent eukaryotic lineage is the ability to couple oxidative reactions resulting from exposure to sunlight and air with the halogenations of various substrates, thereby addressing various biotic and abiotic stresses i.e., defense against predators, tissue repair, holdfast adhesion, and protection against reactive species generated by oxidative processes. Whereas marine organisms mainly make use of bromine to increase the biological activity of secondary metabolites, some orders of brown algae such as Laminariales have also developed a striking capability to accumulate and to use iodine in physiological adaptations to stress. We review selected aspects of the halogenated metabolism of macrophytic brown algae in the light of the most recent results, which point toward novel functions for iodide accumulation in kelps and the importance of bromination in cell wall modifications and adhesion properties of brown algal propagules. The importance of halogen speciation processes ranges from microbiology to biogeochemistry, through enzymology, cellular biology and ecotoxicology.

  15. Dieback of rose caused by Acremonium sclerotigenum as a new causal agent of rose dieback in Iran

    International Nuclear Information System (INIS)

    Mirtalebi, M.; Banihashemi, Z.; Sabahi, F.; Mafakheri, H.

    2016-01-01

    Severe dieback of rose has been recently observed in several rose greenhouses in Fars province of Iran. During 2014 and 2015, stems of rose plants showing yellow to brown discoloration and dieback were collected from rose greenhouses. Coniothyrium fuckelii, Botrytis cinerea and Acremonium were subsequently isolated from the margin between healthy and symptomatic tissue. B. cinerea and C. fuckelii isolates were similar to those previously reported for dieback of rose worldwide. Morphological and cultural characters along with molecular analysis based on partial sequences of the internal transcribed spacer (ITS) region of the ribosomal RNA genome allowed confirming the affiliation of the Acremonium isolates, corresponding to A. sclerotigenum as a new causal agent of rose dieback. To determine its pathogenicity on rose, Koch's postulates were fulfilled by stem inoculation of nine rose cultivars under greenhouse conditions. While A. sclerotigenum is considered as a soil-born pathogen, and produces sclerotia that are resistant to adverse conditions enables the fungus to survive extended period in soil, propagule trapping in our study revealed that conidia can become airborn, imply that an aerial phase, forms an important component of the disease cycle.

  16. Transcriptional Analysis Allows Genome Reannotation and Reveals that Cryptococcus gattii VGII Undergoes Nutrient Restriction during Infection

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    Patrícia Aline Gröhs Ferrareze

    2017-08-01

    Full Text Available Cryptococcus gattii is a human and animal pathogen that infects healthy hosts and caused the Pacific Northwest outbreak of cryptococcosis. The inhalation of infectious propagules can lead to internalization of cryptococcal cells by alveolar macrophages, a niche in which C. gattii cells can survive and proliferate. Although the nutrient composition of macrophages is relatively unknown, the high induction of amino acid transporter genes inside the phagosome indicates a preference for amino acid uptake instead of synthesis. However, the presence of countable errors in the R265 genome annotation indicates significant inhibition of transcriptomic analysis in this hypervirulent strain. Thus, we analyzed RNA-Seq data from in vivo and in vitro cultures of C. gattii R265 to perform the reannotation of the genome. In addition, based on in vivo transcriptomic data, we identified highly expressed genes and pathways of amino acid metabolism that would enable C. gattii to survive and proliferate in vivo. Importantly, we identified high expression in three APC amino acid transporters as well as the GABA permease. The use of amino acids as carbon and nitrogen sources, releasing ammonium and generating carbohydrate metabolism intermediaries, also explains the high expression of components of several degradative pathways, since glucose starvation is an important host defense mechanism.

  17. Albino mutation rates in red mangroves (Rhizophora mangle L.) as a bioassay of contamination history in Tampa Bay, Florida, USA

    Science.gov (United States)

    Proffitt, C.E.; Travis, S.E.

    2005-01-01

    We assessed the sensitivity of a viviparous estuarine tree species, Rhizophora mangle, to historic sublethal mutagenic stress across a fine spatial scale by comparing the frequency of trees producing albino propagules in historically contaminated (n=4) and uncontaminated (n=11) forests in Tampa Bay, Florida, USA. Data from uncontaminated forests were used to provide estimates of background mutation rates. We also determined whether other fitness parameters were negatively correlated with mutagenic stress (e.g., degree of outcrossing and numbers of reproducing trees km-1). Contaminated sites in Tampa Bay had significantly higher frequencies of trees that were heterozygous for albinism per 1000 total reproducing trees (FHT) than uncontaminated forests (mean ?? SE: 11.4 ?? 4.3 vs 4.3 ?? 0.73, P 25 yrs of subsequent recruitment and tree replacement may have allowed an initial elevation in the FHT to decay. Patterns of FHT were not explained by distance from the bay mouth or the degree of urbanization. However, there was a significant positive relationship between tree size and FHT (r=0.83, Pbioassay for the effects of mutagens will facilitate future monitoring of contamination events and comparisons of bay-wide recovery in future decades. Development of a database of FHT values for a range of subtropical and tropical estuaries is underway that will provide a baseline against which to compare mutational consequences of global change. ?? 2005, The Society of Wetland Scientists.

  18. Depth-dependent mortality of reef corals following a severe bleaching event: implications for thermal refuges and population recovery [v3; ref status: indexed, http://f1000r.es/2zg

    Directory of Open Access Journals (Sweden)

    Tom C. L. Bridge

    2014-02-01

    Full Text Available Coral bleaching caused by rising sea temperature is a primary cause of coral reef degradation. However, bleaching patterns often show significant spatial variability, therefore identifying locations where local conditions may provide thermal refuges is a high conservation priority. Coral bleaching mortality often diminishes with increasing depth, but clear depth zonation of coral communities and putative limited overlap in species composition between deep and shallow reef habitats has led to the conclusion that deeper reef habitats will provide limited refuge from bleaching for most species. Here, we show that coral mortality following a severe bleaching event diminished sharply with depth. Bleaching-induced mortality of Acropora was approximately 90% at 0-2m, 60% at 3-4 m, yet at 6-8m there was negligible mortality. Importantly, at least two-thirds of the shallow-water (2-3 m Acropora assemblage had a depth range that straddled the transition from high to low mortality. Cold-water upwelling may have contributed to the lower mortality observed in all but the shallowest depths. Our results demonstrate that, in this instance, depth provided a refuge for individuals from a high proportion of species in this Acropora-dominated assemblage. The persistence of deeper populations may provide a critical source of propagules to assist recovery of adjacent shallow-water reefs.

  19. Depth-dependent mortality of reef corals following a severe bleaching event: implications for thermal refuges and population recovery [v2; ref status: indexed, http://f1000r.es/26m

    Directory of Open Access Journals (Sweden)

    Tom C. L. Bridge

    2013-10-01

    Full Text Available Coral bleaching caused by rising sea temperature is a primary cause of coral reef degradation. However, bleaching patterns often show significant spatial variability, therefore identifying locations where local conditions may provide thermal refuges is a high conservation priority. Coral bleaching mortality often diminishes with increasing depth, but clear depth zonation of coral communities and putative limited overlap in species composition between deep and shallow reef habitats has led to the conclusion that deeper reef habitats will provide limited refuge from bleaching for most species. Here, we show that coral mortality following a severe bleaching event diminished sharply with depth. Bleaching-induced mortality of Acropora was approximately 90% at 0-2m, 60% at 3-4 m, yet at 6-8m there was negligible mortality. Importantly, at least two-thirds of the shallow-water (2-3 m Acropora assemblage had a depth range that straddled the transition from high to low mortality. Cold-water upwelling may have contributed to the lower mortality observed in all but the shallowest depths. Our results demonstrate that, in this instance, depth provided a refuge for individuals from a high proportion of species in this Acropora-dominated assemblage. The persistence of deeper populations may provide a critical source of propagules to assist recovery of adjacent shallow-water reefs.

  20. Assessing invasion process through pathway and vector analysis: case of saltcedar (Tamarix spp.

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    Evangelina Natale

    2012-12-01

    Full Text Available Biological invasions are one of the most pervasive environmental threats to native ecosystems worldwide. The spontaneous spread ofsaltcedar is a particular threat to biodiversity conservation in arid and semiarid environments. In Argentina, three species belonging to this genus have been recognized as invaders. The aim of the present study was to identify main dispersal vectors and pathways to refine risk analysis and increase our ability to predict new areas at risk of Tamarix establishment. We surveyed and categorized 223 populations, 39% as invasive, 26% as established, 21% as contained and 14% as detected in nature. Dispersion of saltcedar was found to be associated with watercourses and human-driven disturbances; in addition roads were found to be relevant for the introduction of propagules in newenvironments. Considering the potential impact of saltcedar invasion and that it is an easily wind-dispersed invasive, it is necessary toimplement strategies to monitor dispersal pathways and take actions to eliminate invasion foci, particularly in vulnerable and highconservation value areas.

  1. Coupling Biophysical and Socioeconomic Models for Coral Reef Systems in Quintana Roo, Mexican Caribbean

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    Jessica Melbourne-Thomas

    2011-09-01

    Full Text Available Transdisciplinary approaches that consider both socioeconomic and biophysical processes are central to understanding and managing rapid change in coral reef systems worldwide. To date, there have been limited attempts to couple the two sets of processes in dynamic models for coral reefs, and these attempts are confined to reef systems in developed countries. We present an approach to coupling existing biophysical and socioeconomic models for coral reef systems in the Mexican state of Quintana Roo. The biophysical model is multiscale, using dynamic equations to capture local-scale ecological processes on individual reefs, with reefs connected at regional scales by the ocean transport of larval propagules. The agent-based socioeconomic model simulates changes in tourism, fisheries, and urbanization in the Quintana Roo region. Despite differences in the formulation and currencies of the two models, we were able to successfully modify and integrate them to synchronize and define information flows and feedbacks between them. A preliminary evaluation of the coupled model system indicates that the model gives reasonable predictions for fisheries and ecological variables and can be used to examine scenarios for future social-ecological change in Quintana Roo. We provide recommendations for where efforts might usefully be focused in future attempts to integrate models of biophysical and socioeconomic processes, based on the limitations of our coupled system.

  2. Limnoperna fortunei Dunker, 1857 larvae in different environments of a Neotropical floodplain: relationships of abiotic variables and phytoplankton with different stages of development

    Directory of Open Access Journals (Sweden)

    J. Ernandes-Silva

    Full Text Available Abstract Limnoperna fortunei Dunker, 1857 is an Asian invasive freshwater bivalve. Although there need to contain their spread, studies about the biology of the larvae are scarce. We correlated the larval stages of L. fortunei with biotic factors such as phytoplankton and main abiotic variables in lotic environments of the Upper Paraná River floodplain. The four samples were taken quarterly during the year 2012. The Principal component analysis (PCA showed only spatial differences, as did a Canonical Correspondence Analysis (CCA. High densities of larvae were recorded in all samples the Paraná River and Baía River only in December, especially those in their initial stage. In the biovolume of Class of algae, Bacillarophyceae showed the highest value, but Chlorophycea who was strongly correlated with the density of D-stage larvae. The large variety of phytoplankton, especially microplankton Chlorophyceae, high values of PO4, NH4 and temperature were positively correlated with high densities of D-stage larvae. We conclude that high temperature, and food availability, indicated by phytoplankton community, favored the reproduction of L. fortunei and enhance the ability of specie dispersion due to the increase in the emission of propagules. Therefore, studies that address the biology of golden mussel larvae should be performed in order to prevent its spread.

  3. The Footprint of Continental-Scale Ocean Currents on the Biogeography of Seaweeds

    Science.gov (United States)

    Wernberg, Thomas; Thomsen, Mads S.; Connell, Sean D.; Russell, Bayden D.; Waters, Jonathan M.; Zuccarello, Giuseppe C.; Kraft, Gerald T.; Sanderson, Craig; West, John A.; Gurgel, Carlos F. D.

    2013-01-01

    Explaining spatial patterns of biological organisation remains a central challenge for biogeographic studies. In marine systems, large-scale ocean currents can modify broad-scale biological patterns by simultaneously connecting environmental (e.g. temperature, salinity and nutrients) and biological (e.g. amounts and types of dispersed propagules) properties of adjacent and distant regions. For example, steep environmental gradients and highly variable, disrupted flow should lead to heterogeneity in regional communities and high species turnover. In this study, we investigated the possible imprint of the Leeuwin (LC) and East Australia (EAC) Currents on seaweed communities across ~7,000 km of coastline in temperate Australia. These currents flow poleward along the west and east coasts of Australia, respectively, but have markedly different characteristics. We tested the hypothesis that, regional seaweed communities show serial change in the direction of current flow and that, because the LC is characterised by a weaker temperature gradient and more un-interrupted along-shore flow compared to the EAC, then coasts influenced by the LC have less variable seaweed communities and lower species turnover across regions than the EAC. This hypothesis was supported. We suggest that this pattern is likely caused by a combination of seaweed temperature tolerances and current-driven dispersal. In conclusion, our findings support the idea that the characteristics of continental-scale currents can influence regional community organisation, and that the coupling of ocean currents and marine biological structure is a general feature that transcends taxa and spatial scales. PMID:24260352

  4. Kelps’ Long-Distance Dispersal: Role of Ecological/Oceanographic Processes and Implications to Marine Forest Conservation

    Directory of Open Access Journals (Sweden)

    Manuela Bernardes Batista

    2018-02-01

    Full Text Available Long-distance dispersal is one of the main drivers structuring the distribution of marine biodiversity. This study reports the first occurrence of Macrocystis pyrifera and Durvillaea antarctica rafts on the southwestern warm temperate coast of the Atlantic Ocean. Our results indicate that an extreme meteo-oceanographic event, characterized by a northward, displacement of cold sub-Antarctic oceanic waters driven by an extratropical cyclone, could account for these unusual occurrences. A niche model based on known current distribution and maximum entropy principle (MAXENT, revealed the availability of suitable habitats at lower latitudes, outside their actual distribution edges. The distributional boundaries, mainly driven by temperature and irradiance, suggest the existence of environmental suitability in warm temperate areas, as well as in the Northern Hemisphere off Atlantic and Asian coasts. These theoretical edges and respective environmental drivers agree with the physiological affinities of both species, supporting the hypothesis that these variables act as limiting factors for their occurrences in tropical or warmer areas. Emerging regions can function as refuges and stepping-stones, providing substrate with adequate habitat conditions for recruitment of propagules, allowing eventual colonization. Long dispersal events reinforce the need for an extensive discussion on selective management of natural dispersion, biological invasions, refuge mapping and conservation initiatives in a transnational perspective.

  5. The role of wrack deposits for supralittoral arthropods: An example using Atlantic sandy beaches of Brazil and Spain

    Science.gov (United States)

    Ruiz-Delgado, Mª Carmen; Vieira, Jenyffer Vierheller; Veloso, Valéria Gomes; Reyes-Martínez, Mª José; Sallorenzo, Ilana Azevedo; Borzone, Carlos Alberto; Sánchez-Moyano, Juan Emilio; García García, Francisco José

    2014-01-01

    Wrack deposits, as accumulated detritus, are a common feature on beaches worldwide and significantly contribute to the shaping of supralittoral arthropod communities. The composition and relative age of upper-shore deposits influence the structure and taxonomic composition of invertebrate assemblages. Moreover, these influences may vary geographically, depending on the locally prevailing climatic and hydrodynamic conditions. The amount and composition of wrack deposits as well as community attributes (total density, species richness and diversity) were determined on sandy beaches in three distinct geographical regions: South (Paraná) and Southeast (Rio de Janeiro) of Brazil and SW Spain. These parameters were compared between upper and lower wrack bands on each beach and between beaches in each region. Wrack deposits were composed of mangrove propagules in the Paraná region, by macrophytes, dead invertebrates and macroalgae in Rio de Janeiro region and by seagrass and macroalgae in the SW Spain region. In all regions, the total amount of stranded wrack differed between beaches, but the amount accumulated between bands (i.e upper and lower band) was similar between beaches. Wrack bands shaped the density of common taxa (Talitridae, Tenebrionidae, and Staphylinidae), with consequences for community structures. This result could be due to their preference for specific microhabitats and food sources, which might differ according to the relative age of the wrack deposits. The results suggest that, independent of wrack composition, the distribution of wrack deposits in bands and their relative ages seems to play a role on the structure of supralittoral arthropod assemblages.

  6. Mangrove Crab Ucides cordatus Removal Does Not Affect Sediment Parameters and Stipule Production in a One Year Experiment in Northern Brazil.

    Science.gov (United States)

    Pülmanns, Nathalie; Mehlig, Ulf; Nordhaus, Inga; Saint-Paul, Ulrich; Diele, Karen

    2016-01-01

    Mangrove crabs influence ecosystem processes through bioturbation and/or litter feeding. In Brazilian mangroves, the abundant and commercially important crab Ucides cordatus is the main faunal modifier of microtopography establishing up to 2 m deep burrows. They process more than 70% of the leaf litter and propagule production, thus promoting microbial degradation of detritus and benefiting microbe-feeding fiddler crabs. The accelerated nutrient turn-over and increased sediment oxygenation mediated by U. cordatus may enhance mangrove tree growth. Such positive feed-back loop was tested in North Brazil through a one year crab removal experiment simulating increased harvesting rates in a mature Rhizophora mangle forest. Investigated response parameters were sediment salinity, organic matter content, CO2 efflux rates of the surface sediment, and reduction potential. We also determined stipule fall of the mangrove tree R. mangle as a proxy for tree growth. Three treatments were applied to twelve experimental plots (13 m × 13 m each): crab removal, disturbance control and control. Within one year, the number of U. cordatus burrows inside the four removal plots decreased on average to 52% of the initial number. Despite this distinct reduction in burrow density of this large bioturbator, none of the measured parameters differed between treatments. Instead, most parameters were clearly influenced by seasonal changes in precipitation. Hence, in the studied R. mangle forest, abiotic factors seem to be more important drivers of ecosystem processes than factors mediated by U. cordatus, at least within the studied timespan of one year.

  7. Bikini Atoll coral biodiversity resilience five decades after nuclear testing

    International Nuclear Information System (INIS)

    Richards, Zoe T.; Beger, Maria; Pinca, Silvia; Wallace, Carden C.

    2008-01-01

    Five decades after a series of nuclear tests began, we provide evidence that 70% of the Bikini Atoll zooxanthellate coral assemblage is resilient to large-scale anthropogenic disturbance. Species composition in 2002 was assessed and compared to that seen prior to nuclear testing. A total of 183 scleractinian coral species was recorded, compared to 126 species recorded in the previous study (excluding synonomies, 148 including synonomies). We found that 42 coral species may be locally extinct at Bikini. Fourteen of these losses may be pseudo-losses due to inconsistent taxonomy between the two studies or insufficient sampling in the second study, however 28 species appear to represent genuine losses. Of these losses, 16 species are obligate lagoonal specialists and 12 have wider habitat compatibility. Twelve species are recorded from Bikini for the first time. We suggest the highly diverse Rongelap Atoll to the east of Bikini may have contributed larval propagules to facilitate the partial resilience of coral biodiversity in the absence of additional anthropogenic threats

  8. PENGARUH PENGGUNAAN PUPUK UREA DAN APLIKASI HERBISIDA PRA-TUMBUH TERHADAP PERTUMBUHAN BIBIT KARET (Hevea brasiliensis Muell.Arg. DAN GULMA DI PEMBIBITAN

    Directory of Open Access Journals (Sweden)

    Yakup Parto

    2012-09-01

    Full Text Available A Research was carried out at green house of Agriculture Faculty of Sriwijaya University from October 2010 to January 2011 using split-split plot design. Main plot were pre-emergence herbicides :  H0 = no preemergence herbicide treatment (control, H1 = preemergence herbicide of methyl metsulfuron, and H2 = preemergence herbicide of ametryn. Subplot were dose of urea fertilizers : U0 = no urea fertilizer treatment (control, U1 = 2 gram of urea fertilizer per plant, and U2 = 4 gram of urea fertilizer per plant. Sub-sub plot were preemergence dosages : D0 = 0 liter formulation per ha, D1 = 1,5 liter formulation per ha, and D2 = 3,0 liter formulation per ha. Parameters measured were diameter of sleep eye stum, time of bud emergence, height of bud, number of leaves, percentage of growth seedling, weed growth, and efficiency of weed control. Results showed that kind of preemergence herbicides, urea fertilizer dosages, and preemergence herbicide dosages were no significant effect to weed dry weight due to weed growing were relative small. This supposed because soil which used as growth media no enough contain weed propagule, so the following research are need conducted.

  9. Growth responses of maritime sand dune plant species to arbuscular mycorrhizal fungi

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    Mariusz Tadych

    2014-08-01

    Full Text Available In a pot experiment conducted in a greenhouse, the response of 6 plant species dominating in the succession of vegetation of a deflation hollow of the Łeba Bar to inoculation with arbuscular mycorrhizal fungi (AMF was investigated. The inoculum was a mixture of soil, roots and spores of 5 species of AMF with the dominant species Glomus aggregatum. Except for Corynephorus canescens and Festuca rubra subsp. arenaria, both the growth and the dry matter of above-ground parts of plants of Agrostis stolonifera, Ammophila arenaria, Corynephorus canescens, Juncus articulatus and J. balticus inoculated with AMF were higher than those growing in soils lacking infection propagules of these fungi. Inoculation with AMF decreased the dry matter of root: shoot ratios in 5 plant species. This property was not determined in Festuca rubra subsp. arenaria due to the death of all control plants. The level of mycorrhizal infection was low and did not correlate with the growth responses found. The high growth reaction of Juncus spp. to AMF found in this study suggests that the opinion of non-mycotrophy or low dependence of plants of Juncaceae on AMF was based on results of investigations of plants growing in wet sites known to inhibit the formation of mycorrhizae.

  10. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Zellmer, S.D. (Argonne National Lab., IL (United States)); Rastorfer, J.R. (Chicago State Univ., IL (United States). Dept. of Biological Sciences ANL/CSU Cooperative Herbarium, Chicago, IL (United States)); Van Dyke, G.D. (Trinity Christian Coll., Palos Heights, IL (United States). Dept. of Biology)

    1991-07-01

    Implementation of recent federal and state regulations promulgated to protect wetlands makes information on effects of gas pipeline rights-of-way (ROWs) in wetlands essential to the gas pipeline industry. This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth forested wetland sites mapped as Lenawee soils, one mature and one subjected to recent selective logging, were selected in Midland County, Michigan. Changes in the adjacent forest and successional development on the ROW are being documented. Cover-class estimates are being made for understory and ROW plant species using 1 {times}1-m quadrats. Counts are also being made for all woody species with stems < 2 cm in diameter at breast height (dbh) in the same plots used for cover-class estimates. Individual stem diameters and species counts are being recorded for all woody understory and overstory plants with stems {ge}2 cm dbh in 10 {times} 10-m plots. Although analyses of the data have not been completed, preliminary analyses indicate that some destruction of vegetation at the ROW forest edge may have been avoidable during pipeline construction. Rapid regrowth of many native wetland plant species on the ROW occurred because remnants of native vegetation and soil-bearing propagules of existing species survived on the ROW after pipeline construction and seeding operations. 91 refs., 11 figs., 3 tabs.

  11. Factors influencing the abundance of pests in production fields and rates of interception of Dracaena marginata imported from Costa Rica.

    Science.gov (United States)

    Hidalgo, Eduardo; Benjamin, Tamara; Casanoves, Fernando; Sadof, Clifford

    2013-10-01

    Importation of live nursery plants, like Dracaena marginata Lamoureux (Ruscaceae), can provide a significant pathway for the entry of foliar pests from overseas into the United States. We studied the abundance of foliar pests of quarantine importance found on Costa Rican-grown D. marginata. These include five genera of leafhoppers (Heteroptera: Cicadellidae, Oncometopia, Caldweliola, Diestostema, Cypona, and Empoasca), Florida red scale (Heteroptera: Disapididae, Chrysomphalus aoinidum (L.)), katydids (Orthoptera: Tettigoniidae), and a snail (Succinea costarricana von Martens (Gastropoda, Stylommatophora, Succineidae)). In our first study, we examined the rationale behind size restrictions on Dracaena cuttings imported into the United States from Costa Rica. When comparing plant size, no differences were found in the abundance of quarantined pests on small (15-46 cm), medium (46-81 cm), and large (81-152 cm) propagules. In a second study, we estimated monthly abundances of pests in production plots for 1 yr to determine their relationship to rates of interception at U.S. ports. In any given month, pest. There was no relationship between the average monthly frequencies of pest detection in the field and in U.S. inspection ports. Pest detections increased during the 1 mo when average monthly shipments were abnormally high. Our data suggest that off-shore postprocessing efforts to remove pest-infested material from the market stream need to be adjusted to accommodate sharp increases in the volume of shipped plants.

  12. Effect of inoculum density and soil tillage on the development and severity of rhizoctonia root rot.

    Science.gov (United States)

    Schroeder, K L; Paulitz, T C

    2008-03-01

    Rhizoctonia spp. cause substantial yield losses in direct-seeded cereal crops compared with conventional tillage. To investigate the mechanisms behind this increased disease, soils from tilled or direct-seeded fields were inoculated with Rhizoctonia spp. at population densities from 0.8 to 250 propagules per gram and planted with barley (Hordeum vulgare). The incidence and severity of disease did not differ between soils with different tillage histories. Both R. solani AG-8 and R. oryzae stunted plants at high inoculum densities, with the latter causing pre-emergence damping-off. High inoculum densities of both species stimulated early production of crown roots in barley seedlings. Intact soil cores from these same tilled and direct-seeded fields were used to evaluate the growth of Rhizoctonia spp. from colonized oat seeds. Growth of R. oryzae was not affected by previous tillage history. However, R. solani AG-8 grew more rapidly through soil from a long-term direct-seeded field compared to tilled soils. The differential response between these two experiments (mixed, homogenized soil versus intact soil) suggests that soil structure plays a major role in the proliferation of R. solani AG-8 through soils with different tillage histories.

  13. Influence of arbuscular mycorrhizal fungi on antimony phyto-uptake and compartmentation in vegetables cultivated in urban gardens.

    Science.gov (United States)

    Pierart, Antoine; Dumat, Camille; Maes, Arthur QuyManh; Sejalon-Delmas, Nathalie

    2018-01-01

    1. Urban areas are often contaminated with various forms of persistent metal (loid) and emerging contaminants such as antimony (Sb). Thus, in the context of urban agriculture where sustainable practices such as biofertilizers application (arbuscular mycorrhizal fungi, AMF) could improve nutrient transfer from the soil to the vegetables, the effect of AMF on metal (loid) mobility and human bioaccessibility is still poorly known. 2. The role of AMF in Sb uptake by lettuce and carrot grown in artificial substrate spiked with different Sb chemical species was investigated. Plants were grown under hydroponic conditions and half of the treatments received a concentrated spore solution to obtain mycorrhized and non-mycorrhized plants. Three weeks before harvest, plants were exposed to 10 mg.L -1 of either Sb 2 O 3 or KSbO-tartrate (KSb). 3. The presence of AMF significantly increased its accumulation in carrots (all organs) with higher accumulation in roots. In lettuce, accumulation appeared to be dependent on the Sb chemical species. Moreover, it was observed for the first time that AMF changed the human bioaccessible fraction of Sb in edible organs. 4. The present results highlight a possible risk of Sb transfer from soil to edible plants cultivated in soil naturally containing AMF propagules, or when AMF are added as biofertilizers. After validating the influence of soil environment and AMF on Sb behavior in the field, these results should be considered in health risk assessments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Sporothrix brasiliensis outbreaks and the rapid emergence of feline sporotrichosis.

    Science.gov (United States)

    Sanchotene, Karine Ortiz; Madrid, Isabel Martins; Klafke, Gabriel Baracy; Bergamashi, Mariana; Della Terra, Paula Portella; Rodrigues, Anderson Messias; de Camargo, Zoilo Pires; Xavier, Melissa Orzechowski

    2015-11-01

    Sporotrichosis is the main subcutaneous mycosis in Brazil, and is caused by Sporothrix schenckii and allied species. Sporothrix propagules present on soil and plant debris may be traumatically inoculated into the cutaneous/ subcutaneous tissues of the warm-blooded host. An alternative route involves direct animal-animal and animal-human transmissions through deep scratches and bites of diseased cats. Sporotrichosis is much more common than previously appreciated with several cases emerging over the years especially in South and Southeast Brazil. We conducted an epidemiological surveillance in endemic areas of feline sporotrichosis in the southern region of Rio Grande do Sul state, Brazil. Over the last 5-year period the number of feline sporotrichosis in Rio Grande increased from 0.75 new cases per month in 2010 to 3.33 cases per month in 2014. The wide geographic distribution of diagnosed cases highlights the dynamics of Sporothrix transmission across urban areas with high population density. Molecular identification down to species level by PCR-RFLP of cat-transmitted Sporothrix revealed the emergence of the clonal offshoot S. brasiliensis during feline outbreaks; this scenario is similar to the epidemics taking place in the metropolitan areas of Rio de Janeiro and São Paulo. Controlling and preventing sporotrichosis outbreaks are essential steps to managing the disease among humans and animals. © 2015 Blackwell Verlag GmbH.

  15. Atypical Clinical Presentation of Sporotrichosis Caused by Sporothrix globosa Resistant to Itraconazole.

    Science.gov (United States)

    Fischman Gompertz, Olga; Rodrigues, Anderson M; Fernandes, Geisa F; Bentubo, Henri D L; de Camargo, Zoilo Pires; Petri, Valéria

    2016-06-01

    Sporotrichosis is a polymorphic disease of humans and animals, which is acquired via traumatic inoculation of Sporothrix propagules into cutaneous or subcutaneous tissue. The etiological agents are in a clinical complex, which includes Sporothrix brasiliensis, Sporothrix schenckii, Sporothrix globosa, and Sporothrix luriei, each of which has specific epidemiological and virulence characteristics. Classical manifestation in humans includes a fixed localized lesion at the site of trauma plus lymphocutaneous sporotrichosis with fungal spreading along the lymphatic channels. Atypical sporotrichosis is a challenge to diagnosis because it can mimic many other dermatological diseases. We report an unusual, itraconazole-resistant cutaneous lesion of sporotrichosis in a 66-year-old Brazilian man. Histopathological examination of the skin revealed vascular and fibroblastic proliferation with chronic granulomatous infiltrate composed of multinucleated giant cells. Sporothrix were isolated from the skin lesion, and phylogenetic analyses confirmed it to be sporotrichosis due to S. globosa, a widespread pathogen. Immunoblotting analysis showed several IgG-reactive molecules in autochthonous preparations of the whole cellular proteins (160, 80, 60, 55, 46, 38, 35, and 30 kDa) and exoantigen (35 and 33 kDa). The patient was first unsuccessfully treated with daily itraconazole, and then successfully treated with potassium iodide. © The American Society of Tropical Medicine and Hygiene.

  16. The repeated evolution of large seeds on islands.

    Science.gov (United States)

    Kavanagh, Patrick H; Burns, Kevin C

    2014-07-07

    Several plant traits are known to evolve in predictable ways on islands. For example, herbaceous species often evolve to become woody and species frequently evolve larger leaves, regardless of growth form. However, our understanding of how seed sizes might evolve on islands lags far behind other plant traits. Here, we conduct the first test for macroevolutionary patterns of seed size on islands. We tested for differences in seed size between 40 island-mainland taxonomic pairings from four island groups surrounding New Zealand. Seed size data were collected in the field and then augmented by published seed descriptions to produce a more comprehensive dataset. Seed sizes of insular plants were consistently larger than mainland relatives, even after accounting for differences in growth form, dispersal mode and evolutionary history. Selection may favour seed size increases on islands to reduce dispersibility, as long-distance dispersal may result in propagule mortality at sea. Alternatively, larger seeds tend to generate larger seedlings, which are more likely to establish and outcompete neighbours. Our results indicate there is a general tendency for the evolution of large seeds on islands, but the mechanisms responsible for this evolutionary pathway have yet to be fully resolved. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  17. Location Isn't Everything: Timing of Spawning Aggregations Optimizes Larval Replenishment.

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    Megan J Donahue

    Full Text Available Many species of reef fishes form large spawning aggregations that are highly predictable in space and time. Prior research has suggested that aggregating fish derive fitness benefits not just from mating at high density but, also, from oceanographic features of the spatial locations where aggregations occur. Using a probabilistic biophysical model of larval dispersal coupled to a fine resolution hydrodynamic model of the Florida Straits, we develop a stochastic landscape of larval fitness. Tracking virtual larvae from release to settlement and incorporating changes in larval behavior through ontogeny, we found that larval success was sensitive to the timing of spawning. Indeed, propagules released during the observed spawning period had higher larval success rates than those released outside the observed spawning period. In contrast, larval success rates were relatively insensitive to the spatial position of the release site. In addition, minimum (rather than mean larval survival was maximized during the observed spawning period, indicating a reproductive strategy that minimizes the probability of recruitment failure. Given this landscape of larval fitness, we take an inverse optimization approach to define a biological objective function that reflects a tradeoff between the mean and variance of larval success in a temporally variable environment. Using this objective function, we suggest that the length of the spawning period can provide insight into the tradeoff between reproductive risk and reward.

  18. Dispersal similarly shapes both population genetics and community patterns in the marine realm

    KAUST Repository

    Chust, Guillem

    2016-06-27

    Dispersal plays a key role to connect populations and, if limited, is one of the main processes to maintain and generate regional biodiversity. According to neutral theories of molecular evolution and biodiversity, dispersal limitation of propagules and population stochasticity are integral to shaping both genetic and community structure. We conducted a parallel analysis of biological connectivity at genetic and community levels in marine groups with different dispersal traits. We compiled large data sets of population genetic structure (98 benthic macroinvertebrate and 35 planktonic species) and biogeographic data (2193 benthic macroinvertebrate and 734 planktonic species). We estimated dispersal distances from population genetic data (i.e., FST vs. geographic distance) and from β-diversity at the community level. Dispersal distances ranked the biological groups in the same order at both genetic and community levels, as predicted by organism dispersal ability and seascape connectivity: macrozoobenthic species without dispersing larvae, followed by macrozoobenthic species with dispersing larvae and plankton (phyto- and zooplankton). This ranking order is associated with constraints to the movement of macrozoobenthos within the seabed compared with the pelagic habitat. We showed that dispersal limitation similarly determines the connectivity degree of communities and populations, supporting the predictions of neutral theories in marine biodiversity patterns.

  19. Thermal Limits and Thresholds of Red Sea Biota

    KAUST Repository

    Chaidez, Veronica

    2018-05-01

    As ocean temperatures continue to rise, the effect of temperature on marine organisms becomes highly relevant. The Red Sea is the warmest sea and is rapidly warming with current surface temperatures (28 – 34 °C) already exceeding those of most tropical systems. This has major consequences for organisms that may already find themselves at their thermal limits. The aim of this project was to define the thermal limits and thresholds of certain Red Sea species. Firstly, to better understand the thermal regimes of the Red Sea, we looked at decadal trends in maximum sea surface temperature across the basin. Then, we tested the thermal capacities of Red Sea mangroves and zooplankton, two key ecological groups, by performing thermal stress experiments in the laboratory. We found that the Red Sea basin is warming faster than the global average (0.17 °C decade-1), the thermal limit of mangrove propagules is between 33 and 35 °C, and the limits among the most common zooplankton groups range from 30 to 36 °C. This project gives us a better understanding of how organisms respond to extreme temperatures and how they may be affected in a future, warmer, ocean.

  20. Phenology and Growth dynamics of Avicennia marina in the Central Red Sea

    KAUST Repository

    Almahasheer, Hanan

    2016-11-28

    The formation of nodes, stem elongation and the phenology of stunted Avicennia marina was examined in the Central Red Sea, where Avicennia marina is at the limit of its distribution range and submitted to extremely arid conditions with salinity above 38 psu and water temperature as high as 35° C. The annual node production was rather uniform among locations averaging 9.59 node y−1, which resulted in a plastocron interval, the interval in between production of two consecutive nodes along a stem, of 38 days. However, the internodal length varied significantly between locations, resulting in growth differences possibly reflecting the environmental conditions of locations. The reproductive cycle lasted for approximately 12 months, and was characterized by peak flowering and propagule development in November and January. These phenological observations provide a starting point for research and restoration programs on the ecology of mangroves in the Central Red Sea, while the plastochrone index reported here would allow calculations of the growth and production of the species from simple morphological measurements.

  1. Unisexual reproduction of Cryptococcus gattii.

    Directory of Open Access Journals (Sweden)

    Sujal S Phadke

    Full Text Available Cryptococcus gattii is a basidiomycetous human fungal pathogen that typically causes infection in tropical and subtropical regions and is responsible for an ongoing outbreak in immunocompetent individuals on Vancouver Island and in the Pacific Northwest of the US. Pathogenesis of this species may be linked to its sexual cycle that generates infectious propagules called basidiospores. A marked predominance of only one mating type (α in clinical and environmental isolates suggests that a-α opposite-sex reproduction may be infrequent or geographically restricted, raising the possibility of an alternative unisexual cycle involving cells of only α mating type, as discovered previously in the related pathogenic species Cryptococcus neoformans. Here we report observation of hallmark features of unisexual reproduction in a clinical isolate of C. gattii (isolate 97/433 and describe genetic and environmental factors conducive to this sexual cycle. Our results are consistent with population genetic evidence of recombination in the largely unisexual populations of C. gattii and provide a useful genetic model for understanding how novel modes of sexual reproduction may contribute to evolution and virulence in this species.

  2. Lagrangian Flow Network: a new tool to evaluate connectivity and understand the structural complexity of marine populations

    Science.gov (United States)

    Rossi, V.; Dubois, M.; Ser-Giacomi, E.; Monroy, P.; Lopez, C.; Hernandez-Garcia, E.

    2016-02-01

    Assessing the spatial structure and dynamics of marine populations is still a major challenge for ecologists. The necessity to manage marine resources from a large-scale perspective and considering the whole ecosystem is now recognized but the absence of appropriate tools to address these objectives limits the implementation of globally pertinent conservation planning. Inspired from Network Theory, we present a new methodological framework called Lagrangian Flow Network which allows a systematic characterization of multi-scale dispersal and connectivity of early life history stages of marine organisms. The network is constructed by subdividing the basin into an ensemble of equal-area subregions which are interconnected through the transport of propagules by ocean currents. The present version allows the identification of hydrodynamical provinces and the computation of various connectivity proxies measuring retention and exchange of larvae. Due to our spatial discretization and subsequent network representation, as well as our Lagrangian approach, further methodological improvements are handily accessible. These future developments include a parametrization of habitat patchiness, the implementation of realistic larval traits and the consideration of abiotic variables (e.g. temperature, salinity, planktonic resources...) and their effects on larval production and survival. While the model is potentially tunable to any species whose biological traits and ecological preferences are precisely known, it can also be used in a more generic configuration by efficient computing and analysis of a large number of experiments with relevant ecological parameters. It permits a better characterization of population connectivity at multiple scales and it informs its ecological and managerial interpretations.

  3. Assessment of the Effectiveness of Ectomycorrhizal Inocula to Promote Growth and Root Ectomycorrhizal Colonization in Pinus patula Seedlings Using the Most Probable Number Technique

    Directory of Open Access Journals (Sweden)

    Manuel Restrepo-Llano

    2014-01-01

    Full Text Available The aim of this study was to evaluate the response of Pinus patula seedlings to two inocula types: soil from a Pinus plantation (ES and an in vitro produced inoculum (EM. The most probable number method (MPN was used to quantify ectomycorrhizal propagule density (EPD in both inocula in a 7-order dilution series ranging from 100 (undiluted inoculum to 10−6 (the most diluted inoculum. The MPN method allowed establishing differences in the number of infective ectomycorrhizal propagules’ density (EPD (ES=34 per g; EM=156 per g. The results suggest that the EPD of an inoculum may be a key factor that influences the successfulness of the inoculation. The low EPD of the ES inoculum suggests that soil extracted from forest plantations had very low effectiveness for promoting root colonization and plant growth. In contrast, the high EPD found in the formulated inoculum (EM reinforced the idea that it is better to use proven high quality inocula for forest nurseries than using soil from a forestry plantation.

  4. Impact of different cropping conditions and tillage practices on the soil fungal abundance of a Phaeozem luvico

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, R.P.; Aulicino, M.B.; Mónaco, C.I.; Kripelz, N.; Cordo, C.A.

    2015-07-01

    Fungal diversity seems to be a good indicator of ecosystem disturbance and functioning. The purpose of this work was to quantify the fungal population as a sensitive indicator of the changes caused by stubble placement in two tillage systems: reduced tillage (RT) and conventional tillage (CT) with and without cropping. To this end, we determined the effect of soil disturbances such as N fertilization, tillage practice, and cropped area on the soil fungal communities of a Phaeozem luvico of the El Salado river basin (Argentina). Soil samples (at 0-10 cm depth) were collected from a field cultivated with wheat at post-harvest, before sowing and at tillering. The relative abundance of individuals of the fungal population was studied on Nash Snyder and Oxgall agar media after different treatments and assessed as colony forming units (CFU/gof soil). The diversity of the fungal population was studied by Shannon´s index (H). The tillage system showed a marked effect only at post-harvest and the number of propagules was highest under RT for both culture media. The largest values of H were found only at post-harvest when Oxgall agar was used. A significant decrease in the values of H was observed when CT and high fertilization was applied in the wheat cropped area. The relative abundance of individuals of the fungal population was different in soils under the different tillage practices. (Author)

  5. Effects of tillage technologies and application of biopreparations on micromycetes in the rhizosphere and rhizoplane of spring wheat

    Science.gov (United States)

    Shirokikh, I. G.; Kozlova, L. M.; Shirokikh, A. A.; Popov, F. A.; Tovstik, E. V.

    2017-07-01

    The population density and structure of complexes of soil microscopic fungi in the rhizosphere and rhizoplane of spring wheat ( Triticum aestivum L.), plant damage by root rot and leaf diseases, and crop yield were determined in a stationary field experiment on a silty loamy soddy-podzolic soil (Albic Retisol (Loamic, Aric)) in dependence on the soil tillage technique: (a) moldboard plowing to 20-22 cm and (b) non-inversive tillage to 14-16 cm. The results were treated with the two-way ANOVA method. It was shown that the number of fungal propagules in the rhizosphere and rhizoplane of plants in the variant with non-inversive tillage was significantly smaller than that in the variant with plowing. Minimization of the impact on the soil during five years led to insignificant changes in the structure of micromycete complexes in the rhizosphere of wheat. The damage of the plants with root rot and leaf diseases upon non-inversive tillage did not increase in comparison with that upon plowing. Wheat yield in the variant with non-inversive tillage was insignificantly lower than that in the variant with moldboard plowing. The application of biopreparations based on the Streptomyces hygroscopicus A4 and Pseudomonas aureofaciens BS 1393 resulted in a significant decrease of plant damage with leaf rust.

  6. Reproductive effort and seasonality associated with male-biased parasitism in Gracilinanus agilis (Didelphimorphia: Didelphidae) infected by Eimeria spp. (Apicomplexa: Eimeriidae) in the Brazilian cerrado.

    Science.gov (United States)

    Strona, A L S; Levenhagem, M; Leiner, N O

    2015-07-01

    The aggregation of parasites among hosts is associated with differential host exposure and susceptibility to parasites, which varies according to host gender, body size, reproductive status and environmental factors. We evaluated the role of these factors on infestation by Eimeria spp. (Eimeriidae) in the agile gracile mouse opossum (Gracilinanus agilis), a semelparous didelphid inhabiting neotropical savannahs. Eimeria spp. abundance and prevalence among G. agilis were associated with the breeding status of individuals and to a lesser extent to climatic season, with both sexes presenting higher Eimeria spp. burdens during late breeding/wet season. On the other hand, male-biased parasitism was restricted to dry/mating season. We suggest that male spatial organization and diet may account for increased parasite burdens within this sex, although future studies should evaluate the role of physiological differences associated with androgen hormones. Finally, a rapid increase in Eimeria spp. loads among females during the late breeding/wet season seems associated with seasonal changes in susceptibility, due to breeding costs related to semelparity, and exposure to infective propagules, while male-die off seems to explain maintenance of higher Eimeria spp. burdens within this sex in the same period.

  7. Re-vegetation of block-cut and milled peatlands: an Estonian example

    Directory of Open Access Journals (Sweden)

    T. Triisberg

    2011-06-01

    Full Text Available The re-vegetation of mined peatlands after abandonment is often a long-lasting process. The aim of this study was to clarify the factors influencing the re-vegetation of abandoned block-cut, milled and fertilised peat areas in Estonia by investigating and comparing their present vegetation. The analysis is based on 285 quadrat samples where plant species composition and cover were assessed, and the pH and electrical conductivity of bog water were measured. Whereas re-vegetation in the block-cut area was quite fast and progressive, in milled peat areas it was slow and irregular because of the absence of viable propagules and the unfavourable conditions for plant growth. The course of re-vegetation depends considerably upon the peat extraction method, the area and surface microtopography of the mined area, the pH and electrical conductivity of the bog water, and the density at which trees have established on the cutover surface. Plant species richness was most affected by the density of tree saplings, litter cover, former treatment and microtopography. A single application of fertiliser ca 25 years ago did not have a long-term effect on the total number of plant species, but did increase plant cover and the mean number of species per quadrat. On milled peatlands, neither the sowing of Oxycoccus palustris seeds nor the planting of Rubus chamaemorus had the desired effect unless growth conditions for the plants were improved.

  8. New insights into the amphibious life of Biomphalaria glabrata and susceptibility of its egg masses to fungal infection.

    Science.gov (United States)

    Duarte, Glennyha F; Rodrigues, Juscelino; Fernandes, Éverton K K; Humber, Richard A; Luz, Christian

    2015-02-01

    The air-breathing snail Biomphalaria glabrata proliferates in stagnant freshwater, and nothing is known about the survival of eggs in intermittently (rather than perpetually) wet habitats. In the present study their egg masses matured, and juveniles subsequently eclosed and were mobile in a stable water film of transitory habitats simulated by two different simple test devices described here. The viability of eggs maintained in an unstable film however, was diminished. The maturation of egg masses in a water film or in water was significantly prevented by the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae. The efficiency depended on the fungal propagule and test environment. Hyphal bodies were more effective against egg masses than conidia. This appears to be a first report of activity of either entomopathogen against a mollusc. Both devices offer accurate and reproducible conditions to test both biological questions and the effects of substances or pathogens against B. glabrata egg masses in water films. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Ecology and life history of an amoebomastigote, Paratetramitus jugosus, from a microbial mat: new evidence for multiple fission

    Science.gov (United States)

    Enzien, M.; McKhann, H. I.; Margulis, L.

    1989-01-01

    Five microbial habitats (gypsum crust, gypsum photosynthetic community, Microcoleus mat, Thiocapsa scum, and black mud) were sampled for the presence of the euryhaline, rapidly growing amoebomastigote, Paratetramitus jugosus. Field investigations of microbial mats from Baja California Norte, Mexico, and Salina Bido near Matanzas, Cuba, reveal that P. jugosus is most frequently found in the Thiocapsa layer of microbial mats. Various stages of the life history were studied using phase-contrast, differential-interference, and transmission electron microscopy. Mastigote stages were induced and studied by electron microscopy; mastigotes that actively feed on bacteria bear two or more undulipodia. A three-dimensional drawing of the kinetid ("basal apparatus") based on electron micrographs is presented. Although promitoses were occasionally observed, it is unlikely that they can account for the rapid growth of P. jugosus populations on culture media. Dense, refractile, spherical, and irregular-shaped bodies were seen at all times in all cultures along with small mononucleate (approximately 2-7 micrometers diameter) amoebae. Cytochemical studies employing two different fluorescent stains for DNA (DAPI, mithramycin) verified the presence of DNA in these small bodies. Chromatin-like material seen in electron micrographs within the cytoplasm and blebbing off nuclei were interpreted to the chromatin bodies. Our interpretation, consistent with the data but not proven, is that propagation by multiple fission of released chromatin bodies that become small amoebae may occur in Paratetramitus jugosus. These observations are consistent with descriptions of amoeba propagules in the early literature (Hogue, 1914).

  10. Morphodynamic simulation of sediment deposition patterns on a recently stripped bedrock anastomosed channel

    Directory of Open Access Journals (Sweden)

    D. Milan

    2018-04-01

    Full Text Available Some mixed bedrock-alluvial dryland rivers are known to undergo cycles of alluvial building during low flow periods, punctuated by stripping events during rare high magnitude flows. We focus on the Olifants River, Kruger National Park, South Africa, and present 2-D morphodynamic simulations of hydraulics and sediment deposition patterns over an exposed bedrock anastomosed pavement. We examine the assumptions underlying a previous conceptual model, namely that sedimentation occurs preferentially on bedrock highs. Our modelling results and local field observations in fact show that sediment thicknesses are greater over bedrock lows, suggesting these are the key loci for deposition, barform initiation and island building. During peak flows, velocities in the topographic lows tend to be lower than in intermediate topographic areas. It is likely that intermediate topographic areas supply sediment to the topographic lows at this flow stage, which is then deposited in the lows on the falling limb of the hydrograph as velocities reduce. Subsequent vegetation establishment on deposits in the topographic lows is likely to play a key role in additional sedimentation and vegetation succession, both through increasing the cohesive strength of alluvial units and by capturing new sediments and propagules.

  11. Real-Time PCR Detection and QUantification of Soilborne Fungal Pathogens : the Case of Rosellinia necatrix, Phytophthora nicotianae, P. citrophthora and Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    L. Schena

    2004-08-01

    Full Text Available Conventional and Scorpion primers were designed from the ITS regions to identify Rosellinia necatrix, Phytophthora nicotianae, and P. citrophthora and from the IGS regions to identify Verticillium dahliae and V. alboatrum. Specificity of primers and probes was assessed using genomic DNA from a large number of fungi from several hosts and by means of BLAST analyses, to exclude the presence of similar sequences in other micro-organisms among available DNA databases (GenBank. Simple and rapid procedures for DNA extraction from naturally infected matrices (soils, roots, bark, and/or woody tissues were utilised to yield DNA of a purity and quality suitable for PCR assays. Combining these protocols with a double amplification (nested Scorpion-PCR, the real-time detection of these pathogens was possible from naturally infested soils and from infected citrus roots (P. nicotianae and P. citrophthora, from the roots and bark of stone fruits and olive (R. necatrix and from olive branches (V. dahliae. For target pathogens, the limit of detection was 1 pg µl-1 in Scorpion-PCR and 1 fg µl-1 in nested Scorpion-PCR. High and significant correlations between pathogen propagule concentrations and real-time PCR cycle thresholds (Ct were obtained. Moreover, specific tests with R. necatrix seem to indicate that its DNA is quite rapidly degraded in the soil, excluding the risk of false positives due to the presence of dead cells.

  12. Disentangling the role of environmental and human pressures on biological invasions across Europe.

    Science.gov (United States)

    Pysek, Petr; Jarosík, Vojtech; Hulme, Philip E; Kühn, Ingolf; Wild, Jan; Arianoutsou, Margarita; Bacher, Sven; Chiron, Francois; Didziulis, Viktoras; Essl, Franz; Genovesi, Piero; Gherardi, Francesca; Hejda, Martin; Kark, Salit; Lambdon, Philip W; Desprez-Loustau, Marie-Laure; Nentwig, Wolfgang; Pergl, Jan; Poboljsaj, Katja; Rabitsch, Wolfgang; Roques, Alain; Roy, David B; Shirley, Susan; Solarz, Wojciech; Vilà, Montserrat; Winter, Marten

    2010-07-06

    The accelerating rates of international trade, travel, and transport in the latter half of the twentieth century have led to the progressive mixing of biota from across the world and the number of species introduced to new regions continues to increase. The importance of biogeographic, climatic, economic, and demographic factors as drivers of this trend is increasingly being realized but as yet there is no consensus regarding their relative importance. Whereas little may be done to mitigate the effects of geography and climate on invasions, a wider range of options may exist to moderate the impacts of economic and demographic drivers. Here we use the most recent data available from Europe to partition between macroecological, economic, and demographic variables the variation in alien species richness of bryophytes, fungi, vascular plants, terrestrial insects, aquatic invertebrates, fish, amphibians, reptiles, birds, and mammals. Only national wealth and human population density were statistically significant predictors in the majority of models when analyzed jointly with climate, geography, and land cover. The economic and demographic variables reflect the intensity of human activities and integrate the effect of factors that directly determine the outcome of invasion such as propagule pressure, pathways of introduction, eutrophication, and the intensity of anthropogenic disturbance. The strong influence of economic and demographic variables on the levels of invasion by alien species demonstrates that future solutions to the problem of biological invasions at a national scale lie in mitigating the negative environmental consequences of human activities that generate wealth and by promoting more sustainable population growth.

  13. Statistical culture-based strategies to enhance chlamydospore production by Trichoderma harzianum SH2303 in liquid fermentation*

    Science.gov (United States)

    Li, Ya-qian; Song, Kai; Li, Ya-chai; Chen, Jie

    2016-01-01

    Trichoderma-based formulations are applied as commercial biocontrol agents for soil-borne plant pathogens. Chlamydospores are active propagules in Trichoderma spp., but their production is currently limited due to a lack of optimal liquid fermentation technology. In this study, we explored response surface methodologies for optimizing fermentation technology in Trichoderma SH2303. Our initial studies, using the Plackett-Burman design, identified cornmeal, glycerol, and initial pH levels as the most significant factors (P<0.05) for enhancing the production of chlamydospores. Subsequently, we applied the Box-Behnken design to study the interactions between, and optimal levels of, a number of factors in chlamydospore production. These statistically predicted results indicated that the highest number of chlamydospores (3.6×108 spores/ml) would be obtained under the following condition: corn flour 62.86 g/L, glycerol 7.54 ml/L, pH 4.17, and 6-d incubation in liquid fermentation. We validated these predicted values via three repeated experiments using the optimal culture and achieved maximum chlamydospores of 4.5×108 spores/ml, which approximately a 8-fold increase in the number of chlamydospores produced by T. harzianum SH2303 compared with that before optimization. These optimized values could help make chlamydospore production cost-efficient in the future development of novel biocontrol agents. PMID:27487807

  14. Statistical culture-based strategies to enhance chlamydospore production by Trichoderma harzianum SH2303 in liquid fermentation.

    Science.gov (United States)

    Li, Ya-Qian; Song, Kai; Li, Ya-Chai; Chen, Jie

    2016-08-01

    Trichoderma-based formulations are applied as commercial biocontrol agents for soil-borne plant pathogens. Chlamydospores are active propagules in Trichoderma spp., but their production is currently limited due to a lack of optimal liquid fermentation technology. In this study, we explored response surface methodologies for optimizing fermentation technology in Trichoderma SH2303. Our initial studies, using the Plackett-Burman design, identified cornmeal, glycerol, and initial pH levels as the most significant factors (P<0.05) for enhancing the production of chlamydospores. Subsequently, we applied the Box-Behnken design to study the interactions between, and optimal levels of, a number of factors in chlamydospore production. These statistically predicted results indicated that the highest number of chlamydospores (3.6×10(8) spores/ml) would be obtained under the following condition: corn flour 62.86 g/L, glycerol 7.54 ml/L, pH 4.17, and 6-d incubation in liquid fermentation. We validated these predicted values via three repeated experiments using the optimal culture and achieved maximum chlamydospores of 4.5×10(8) spores/ml, which approximately a 8-fold increase in the number of chlamydospores produced by T. harzianum SH2303 compared with that before optimization. These optimized values could help make chlamydospore production cost-efficient in the future development of novel biocontrol agents.

  15. Speciation in ancient cryptic species complexes: evidence from the molecular phylogeny of Brachionus plicatilis (Rotifera).

    Science.gov (United States)

    Gómez, Africa; Serra, Manuel; Carvalho, Gary R; Lunt, David H

    2002-07-01

    Continental lake-dwelling zooplanktonic organisms have long been considered cosmopolitan species with little geographic variation in spite of the isolation of their habitats. Evidence of morphological cohesiveness and high dispersal capabilities support this interpretation. However, this view has been challenged recently as many such species have been shown either to comprise cryptic species complexes or to exhibit marked population genetic differentiation and strong phylogeographic structuring at a regional scale. Here we investigate the molecular phylogeny of the cosmopolitan passively dispersing rotifer Brachionus plicatilis (Rotifera: Monogononta) species complex using nucleotide sequence variation from both nuclear (ribosomal internal transcribed spacer 1, ITS1) and mitochondrial (cytochrome c oxidase subunit I, COI) genes. Analysis of rotifer resting eggs from 27 salt lakes in the Iberian Peninsula plus lakes from four continents revealed nine genetically divergent lineages. The high level of sequence divergence, absence of hybridization, and extensive sympatry observed support the specific status of these lineages. Sequence divergence estimates indicate that the B. plicatilis complex began diversifying many millions of years ago, yet has showed relatively high levels of morphological stasis. We discuss these results in relation to the ecology and genetics of aquatic invertebrates possessing dispersive resting propagules and address the apparent contradiction between zooplanktonic population structure and their morphological stasis.

  16. Implication of evolution and diversity in arbuscular and ectomycorrhizal symbioses.

    Science.gov (United States)

    Buscot, François

    2015-01-01

    Being highly sensitive to ecological variations, symbiotic associations should inherently have a limited occurrence in nature. To circumvent this sensitivity and reach their universal distribution, symbioses used three strategies during their evolution, which all generated high biodiversity levels: (i) specialization to a specific environment, (ii) protection of one partner via its internalization into the other, (iii) frequent partner exchange. Mycorrhizal associations follow the 3rd strategy, but also present traits of internalization. As most ancient type, arbuscular mycorrhiza (AM) formed by a monophyletic fungal group with reduced species richness did constantly support the mineral nutrition of terrestrial plants and enabled their ecological radiation and actual biodiversity level. In contrast ectomycorrhiza (EM) evolved later and independently within different taxa of fungi able to degrade complex organic plant residues, and the diversity levels of EM fungal and tree partners are balanced. Despite their different origins and diversity levels, AM and EM fungi display similar patterns of diversity dynamics in ecosystems. At each time or succession interval, a few dominant and many rare fungi are recruited by plants roots from a wide reservoir of propagules. However, the dominant fungal partners are frequently replaced in relation to changes in the vegetation or ecological conditions. While the initial establishment of AM and EM fungal communities corresponds to a neutral recruitment, their further succession is rather driven by niche differentiation dynamics. Copyright © 2014 The Authors. Published by Elsevier GmbH.. All rights reserved.

  17. Aerobiology of the built environment: Synergy between Legionella and fungi.

    Science.gov (United States)

    Alum, Absar; Isaacs, Galahad Zachariah

    2016-09-02

    The modern built environment (BE) design creates unique ecological niches ideal for the survival and mutual interaction of microbial communities. This investigation focused on the synergistic relations between Legionella and the fungal species commonly found in BEs and the impact of these synergistic relationships on the survival and transmission of Legionella. A field study was conducted to identify the types and concentrations of fungi in BEs. The fungal isolates purified from BEs were cocultured with Legionella to study their synergistic association. Cocultured Legionella cells were aerosolized in an air-tight chamber to evaluate the efficacy of ultraviolet (UV) to inactivate these cells. Aspergillus, Alternaria, and Cladosporium were the most common fungi detected in samples that tested positive for Legionella. After coculturing, Legionella cells were detected inside fungal hyphae. The microscopic observations of Legionella internalization in fungal hyphae were confirmed by molecular analyses. UV disinfection of the aerosolized Legionella cells that were cocultured with fungi indicated that fungal spores and propagules act as a shield against UV radiation. The shield effect of fungal spores on Legionella cells was quantified at >2.5 log10. This study provides the first evidence, to our knowledge, of Legionella cell presence inside fungi detected in an indoor environment. This symbiotic relationship with fungi results in longer survival of Legionella under ambient conditions and provides protection against UV rays. Copyright © 2016. Published by Elsevier Inc.

  18. Genetic diversity in three invasive clonal aquatic species in New Zealand

    Science.gov (United States)

    2010-01-01

    Background Elodea canadensis, Egeria densa and Lagarosiphon major are dioecious clonal species which are invasive in New Zealand and other regions. Unlike many other invasive species, the genetic variation in New Zealand is very limited. Clonal reproduction is often considered an evolutionary dead end, even though a certain amount of genetic divergence may arise due to somatic mutations. The successful growth and establishment of invasive clonal species may be explained not by adaptability but by pre-existing ecological traits that prove advantageous in the new environment. We studied the genetic diversity and population structure in the North Island of New Zealand using AFLPs and related the findings to the number of introductions and the evolution that has occurred in the introduced area. Results Low levels of genetic diversity were found in all three species and appeared to be due to highly homogeneous founding gene pools. Elodea canadensis was introduced in 1868, and its populations showed more genetic structure than those of the more recently introduced of E. densa (1946) and L. major (1950). Elodea canadensis and L. major, however, had similar phylogeographic patterns, in spite of the difference in time since introduction. Conclusions The presence of a certain level of geographically correlated genetic structure in the absence of sexual reproduction, and in spite of random human dispersal of vegetative propagules, can be reasonably attributed to post-dispersal somatic mutations. Direct evidence of such evolutionary events is, however, still insufficient. PMID:20565861

  19. Plant tolerance to mercury in a contaminated soil is enhanced by the combined effects of humic matter addition and inoculation with arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Cozzolino, V; De Martino, A; Nebbioso, A; Di Meo, V; Salluzzo, A; Piccolo, A

    2016-06-01

    In a greenhouse pot experiment, lettuce plants (Lactuca sativa L.) were grown in a Hg-contaminated sandy soil with and without inoculation with arbuscular mycorrhizal fungi (AMF) (a commercial inoculum containing infective propagules of Rhizophagus irregularis and Funneliformis mosseae) amended with different rates of a humic acid (0, 1, and 2 g kg(-1) of soil), with the objective of verifying the synergistic effects of the two soil treatments on the Hg tolerance of lettuce plants. Our results indicated that the plant biomass was significantly increased by the combined effect of AMF and humic acid treatments. Addition of humic matter to soil boosted the AMF effect on improving the nutritional plant status, enhancing the pigment content in plant leaves, and inhibiting both Hg uptake and Hg translocation from the roots to the shoots. This was attributed not only to the Hg immobilization by stable complexes with HA and with extraradical mycorrhizal mycelium in soil and root surfaces but also to an improved mineral nutrition promoted by AMF. This work indicates that the combined use of AMF and humic acids may become a useful practice in Hg-contaminated soils to reduce Hg toxicity to crops.

  20. Culturable fungi in potting soils and compost.

    Science.gov (United States)

    Haas, Doris; Lesch, Susanne; Buzina, Walter; Galler, Herbert; Gutschi, Anna Maria; Habib, Juliana; Pfeifer, Bettina; Luxner, Josefa; Reinthaler, Franz F

    2016-11-01

    In the present study the spectrum and the incidence of fungi in potting soils and compost was investigated. Since soil is one of the most important biotopes for fungi, relatively high concentrations of fungal propagules are to be expected. For detection of fungi, samples of commercial soils, compost and soils from potted plants (both surface and sub-surface) were suspended and plated onto several mycological media. The resulting colonies were evaluated qualitatively and quantitatively. The results from the different sampling series vary, but concentrations on the surface of potted plants and in commercial soils are increased tenfold compared to compost and sub-surface soils. Median values range from 9.5 × 10(4) colony forming units (CFU)/g to 5.5 × 10(5) CFU/g. The spectrum of fungi also varies in the soils. However, all sampling series show high proportion of Aspergillus and Penicillium species, including potentially pathogenic species such as Aspergillus fumigatus. Cladosporium, a genus dominant in the ambient air, was found preferably in samples which were in contact with the air. The results show that potentially pathogenic fungi are present in soils. Immunocompromised individuals should avoid handling soils or potted plants in their immediate vicinity. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.