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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

A preliminary study on the biocontrol of dollar spot (Sclerotinia homeocarpa) and brown patch (Rhizoctonia solani) on creeping bentgrass by an isolate of Streptomyces /

Reuter, Helen M. 01 January 1992 (has links) (PDF)
No description available.
32

Avaliação da atividade antinociceptiva da fração metanólica obtida a partir da biomassa do fungo endofítico da espécie Rhizoctonia solani / Evaluation of antinociceptive and antiinflamatory activity of methanol fraction of the biomass obtained from the endophytic fungus Rhizoctonia solani species

Barros, Betijane Soares de 26 November 2012 (has links)
The Rhizoctonia is a genus belonging to the Fungi Kingdom, whose representatives live in the soil and act as endophytes of various plants. Among the plants possessing this fungus, deserves the red-pepper tree (Schinus terebinthifolius Raddi), which is popularly used for different purposes, including inflammation. This work describes the antinociceptive and antiinflammatory activity of methanolic fraction obtained from the biomass of the endophytic fungus from Rhizoctonia solani. The methanolic fraction, when administered by intraperitoneal route, was able to reduce the nociception induced by acetic acid for a period of 8 h. In addition, the methanolic fraction increased the lag time measured in the model of thermal nociception, thus suggesting a possible central action. The same substance exhibited antinociceptive activity in formalin test in both phase, neurogenic and inflammatory. In search of a possible mechanism of action, we found that among the pharmacological tools used, only naloxan was able to restore the action of the methanolic fraction, thus suggesting that the substance acts via opioid receptor. In the search for a possible anti-inflammatory effect from this methanol fraction, we used the rat paw edema test and found that this fraction was able to significantly inhibit the paw edema induced by carrageenan and PGE2. Using histamine as an inducer of edema, we note that the methanolic fraction was also antiedematogenic. In this model, the reference drugs indomethacin and promethazine inhibited the edema formation. Together, our results show for the first time that the methanolic fraction obtained from the biomass of the endophytic fungus Rhizoctonia solani has a potent antinociceptive and anti-inflammatory. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / A Rhizoctonia é um gênero pertencente ao Reino Fungi, cujos seus representantes habitam o solo e atuam como endofíticos de vários organismos vegetais. Dentre as plantas possuidoras deste fungo, merece destaque a aroeira-vermelha (Schinus terebinthifolius Raddi), que é utilizada popularmente para diferentes finalidades, incluindo inflamação. Este trabalho descreve a atividade antiinflamatória e antinociceptiva da fração metanólica obtida a partir da biomassa do fungo endofítico Rhizoctonia solani. A fração metanólica, quando administrado por via intraperitoneal, foi capaz de reduzir a nocicepção induzida pelo ácido acético por um período de 8 h. Além disso, a fração metanólica aumentou o tempo de latência avaliado no modelo de nocicepção térmica, sugerindo assim uma possível ação central. A mesma substância apresentou atividade antinociceptiva no ensaio de formalina, tanto na fase neurogênica quanto na fase inflamatória. Em busca de um possível mecanismo de ação, verificamos que dentre as ferramentas farmacológicas usadas, apenas a naloxona foi capaz de reverter à ação da fração metanólica, sugerindo assim que a substância age via receptor opióide. Estendendo as análises para uma possível ação antiinflamatória da fração metanólica, utilizamos o ensaio de edema de pata e verificamos que esta fração foi capaz de inibir de modo significativo o edema de pata induzido por carragenina e PGE2. Utilizando-se a histamina como indutor do edema, notamos que a fração metanólica também se mostrou antiedematogênica. Neste modelo, os fármacos de referência indometacina ou prometazina foram capazes de inibir a formação do edema. Juntos, nossos resultados mostram, pela primeira vez, que a fração metanólica obtida a partir da biomassa do fungo endofítico Rhizoctonia solani apresenta uma potente atividade antinociceptiva e antiinflamatória.
33

Avaliação de cultivares de soja [Glycine max (L.) MERRILL] quanto à tolerância à Rhizoctonia solani. / A soybean [Glycine max (L.) Merrill] cultivars assessment for tolerance Rhizoctonia solani.

Ben, Cássio Alberto Vielmo 27 February 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to evaluate the genetic resistance of cultivars for the possible damage caused by Rhizoctonia solani in controlled humidity conditions. For this, the work was divided into parts, which began from the get the pathogen identified in the AG-4 anastomosis group, mainly responsible for causing rot the root system and soybean seedling damping-off. Then the spread was performed in laboratory, cultured in petri dishes, and after standing in a culture medium using corn flour, sand and distilled water, which was evaluated inoculum different doses (0, 5, 15, 25, 40g) in order to adjust the conditions for the damage. For the tests in the greenhouse, all experimental units were formed by a polyethylene tray with a capacity of 2.5 L, containing sterile sand 5.5Kg, with additional fertilizers and 80% of field capacity. For the evaluation of inoculum doses opening was arranged in 5 rows in each tray and the treatments applied to the quantities evaluated with 4 repeated, with a repetition of each tray. Two days after inoculation, 50 seeds were sown in each tray. This procedure was performed twice, each time with a different cultivar. We evaluated the germination and the damage to the root system, considered the end that 25g enough to cause damage. Evaluations were carried germination and sanity 40 cultivars which 10 were selected to be used in the final assay. Finally, selected cultivars were evaluated in a greenhouse in two exposure to the pathogen, with and without R. solani, forming a bi factorial (10x2) with 20 treatments. Emergence were evaluated, and tipping in pre emergency, and morphological analyzes, at 28 DAS, plant height was evaluated, fresh and shoot dry, fresh and dry weight of root and root length and volume. For emergencies, there was no significant difference between cultivars without inoculation, however, in inoculum exposure conditions NS 5959 cultivars, TEC 6070 IRGA and ZIP 64 proved superior. To rot in pre-emergency assessments to grow with higher rates was the BMX NIB, with 53.86% of the seeds. For seedling height, the earliest cultivars showed the highest values, with the NS 5959 and V-TOP with the best rates. Both fresh weight as the shoot dry mass did not differ among cultivars and treatments. The analysis of the root system showed better results for cultivars IRGA TEC 6070, NS 5959, CEP 64 and V-TOP to root length, V-TOP and TEC IRGA 6070 for fresh and dry weight of root and root volume. Pathogen confirmation evaluation, the result was positive for all analyzes. In conclusion, you can see very vulnerable cultivars to R. solani, which is an important pathogen found in lowland conditions and can cause major yield losses. / O objetivo deste trabalho foi avaliar a resistência genética de cultivares comerciais quanto aos possíveis danos causados por Rhizoctonia solani em condições de umidade controlada. Para isso o trabalho foi dividido em partes, onde teve início a partir da obtenção do patógeno identificado no grupo de anastomose AG-4, responsável principalmente por causar podridões ao sistema radicular e tombamento de plântulas de soja. Em seguida foi realizada a sua propagação em laboratório, cultivado em placas de petri, e após em um meio de cultura utilizando farinha de milho, areia e água destilada, onde avaliou-se doses de inóculo distintas (0, 5, 15, 25 e 40 g) visando adequar as condições necessárias para obter os danos. Para os ensaios em casa de vegetação, todas as unidades experimentais foram formadas por uma bandeja de polietileno com capacidade para 2,5 L, contendo 5,5Kg de areia estéril, com adubação complementar e com 80% da capacidade de campo. Para a avaliação das doses de inóculo, procedeu-se a abertura de 5 linhas em cada bandeja e aplicou-se os tratamentos com as quantidades avaliadas, com 4 repetição, sendo cada bandeja uma repetição. Dois dias após a inoculação, foram semeadas 50 sementes em cada bandeja. Esse procedimento foi realizado duas vezes, sendo cada vez, com uma cultivar distinta. Avaliou-se a germinação e os danos causados ao sistema radicular, considerado ao final que 25g suficiente para causar danos. Procedeu-se avaliações de germinação e sanidade de 40 cultivares, onde 10 foram selecionadas para serem utilizadas no ensaio final. Por fim, as cultivares selecionadas foram avaliadas em casa de vegetação em duas condições de exposição ao patógeno, com e sem R. solani, formando um esquema bi fatorial (10x2) com 20 tratamentos. Foram avaliadas emergência de plântulas, e tombamento em pré emergência, e para análises morfológicas, aos 28 DAS, avaliou-se altura de plantas, massa fresca e seca da parte aérea, massa fresca e seca de raiz e comprimento e volume radicular. Para a emergência, não houve diferença significativa entre cultivares sem inoculação, porém, em condições de exposição ao inóculo as cultivares NS 5959, TEC IRGA 6070 e CEP 64 mostraram-se superiores. Para avaliações de podridão em pré-emergência, a cultivar com maiores índices foi a BMX PONTA, com 53,86% das sementes. Para altura de plântulas, as cultivares mais precoces apresentaram os maiores valores, sendo a NS 5959 e V-TOP com os melhores índices. Tanto a massa fresca quanto a massa seca da parte aérea não apresentaram diferenças estatísticas entre cultivares e entre tratamentos. Já a análise do sistema radicular mostrou melhores resultados para as cultivares TEC IRGA 6070, NS 5959, CEP 64 e V-TOP para comprimento radicular, V-TOP e TEC IRGA 6070 para massa fresca e seca de raiz e volume de raiz. Em avaliação de confirmação de patógeno, o resultado foi positivo para todas as análises realizadas. Em conclusão, é possível verificar grande vulnerabilidade de cultivares a R. solani, que é um importante patógeno encontrado em condições de várzea e que pode causar grande perdas de produtividade.
34

INTERACTION BETWEEN MELOIDOGYNE INCOGNITA AND RHIZOCTONIA SOLANI IN SEEDLING DISEASE OF COTTON

Carter, William Whitney, 1941- January 1973 (has links)
No description available.
35

Damping Off

Olsen, Mary W., Young, Deborah 01 1900 (has links)
2 pp. / Originally published: 1998 / Damping off is caused by several different fungi under different environmental conditions. The fungi include Pythium, Rhizoctonia solani, and Thielaviopsis basicola. This article discusses the symptoms, environmental conditions, diseases, prevention and control methods for the damping-off caused by fungi.
36

Polissacarídeos da biomassa do basidiomiceto Rhizoctonia solani : extração, purificação e atividade biológica /

Alexandre, Samara Marrye Aguiar January 2015 (has links)
Orientador: Maria de Lourdes Corradi Custodio da Silva / Banca: Beatriz Eleutério Goi / Banca: Cesar Augusto Tischer / Resumo: O fungo Rhizoctonia solani, é um fitopatógeno que ataca diversas culturas, provocando o tombamento de plântulas. Há vários estudos visando o combate deste micro-organismo, no entanto, não há relatos da composição química de sua biomassa. De acordo com a literatura a biomassa fúngica pode ser uma fonte promissora de moléculas para aplicação em ensaios biológicos. A partir disso, um estudo inédito da composição química da biomassa do R. solani, principalmente em relação aos polissacarídeos, foi realizado. O micro-organismo foi cultivado em meio mínimo de Vogel com glucose como fonte de carbono. A biomassa resultante de vários cultivos foi tratada consecutivamente com etanol (1:20 m/v, 78 °C, 12h, 1x), e água destilada a quente (1:20 m/v, 100 °C, 4h, 4x). O extrato aquoso foi submetido a ciclos de congelamento e descongelamento de maneira a separar o material insolúvel da fração solúvel que foi precipitada em etanol e denominada PEH2O (precipitado etanólico do extrato aquoso). A fração solúvel foi analisada por GPC, cujos resultados indicaram a necessidade de purificação adicional. A cromatografia de filtração em gel Sepharose CL-6B, a pressão normal, separou o PEH2O em cinco frações distintas, denominadas de PI a PV, eluídas em ordem decrescente de suas massas moleculares. A análise cromatográfica para verificar o grau de homogeneidade de cada pico (GPC) indicou que tanto PIII quanto PV estavam puros e aptos a serem quimicamente caracterizados. A hidrólise ácida e os resultados das análises de metilação e ressonância magnética nuclear uni e bidimensional mostraram que PIII é uma β-D-glucana com cadeia principal formada por ligações (1→3), (1→6) e parcialmente substituída em O-6 por cadeias laterais β-D-glucopiranosídicas e PV uma fucomanogalactana com a cadeia principal formada por resíduos α-D-galactopiranosídicos (1→6) ligados, parcialmente substituídos em O-2 por unidades... / Abstract: The Rhizoctonia solani is a phytopathogenic fungus that attacks various crops, causing the tipping of seedlings. There are several studies related to the combat this microorganism, however, no reports of its biomass chemical composition. According to the literature the fungal biomass can be a promising source of molecules for the use in biological studies. Then a novel study of the chemical composition from R. solani biomass, mainly in relation to the polysaccharides, was conducted. The microorganism was grown in Vogel minimal salts medium with glucose as carbon source. Biomass resulting from various cultivations was treated consecutively with ethanol (1:20 w/v), 78 °C, 12h, 1x) and hot distilled water (1:20 w/v, 100 °C, 4h, 4x). The aqueous extract was subjected to freezing and thawing cycles in order to separate the insoluble material. The soluble fraction was precipitated in ethanol and named PEH2O (ethanolic precipitated from aqueous extract). That fraction was analyzed by GPC and the results indicated that an additional purification procedure would be necessary. Gel filtration chromatography on Sepharose CL-6B at normal pressure, separated the PEH2O in five distinct fractions named PI to PV, which eluted in decreasing order of their molecular weight. The chromatographic analysis to verify the homogeneity degree of each peak (GPC) indicated that both PIII as PV were pure and able to be chemically characterized. The results from acid hydrolysis, methylation analysis and uni- and bidimensional nuclear magnetic resonance experiments showed that PIII is a glucan with β-D-Glcp(1→3), (1→6)-linked main chain, partially substituted at O-6 by β-D-Glcp side chains and PV a fucomannogalactan with a main chain composed by (1→6)-linked -D-Galp partially substituted in O-2 by non-reducing end-units of α- L-Fucp and α-D-Manp. Some Galp units from main chain were partially methylated at OH-3. Both... / Mestre
37

The influence of Zn nutritional status on the severity of Rhizoctonia root rot of cereals

Thongbai, Pongmanee. January 1993 (has links) (PDF)
Bibliography: leaves 149-173.
38

Characterisation of rhizoctonia barepatch decline

Wiseman, Bronwyn Meg. January 1996 (has links) (PDF)
Bibliography: leaves 184-209. This thesis describes the occurence of natural, biologically based suppression of Rhizoctonia barepatch in a direct drilled system at Avon, South Australia. The supressive characteristics are transferable, removed by biocidal treatments, and active against increasing doses of R. solani AG-8, Gaeumannomyces graminis var. tritici and Fusarium graminearum. Disease severity and the viable population of Rhizoctonia are reduced in suppressive soil but the causal agent is still present. The microbial populations in suppressive and non-suppressive soil appear to differ both in their functioning and composition. The control strategy is developed through manipulation of the existing soil biota with farming practices.
39

The effects of trifluralin and Rhizoctonia solani on cotton seedlings

Agamalian, Harry Samson, 1929- January 1964 (has links)
No description available.
40

Development of a specific and reliable molecular marker to detect Stachybrotyrs [i.e. Stachybotrys] elegans, a destructive mycoparasite of Rhizoctonia solani

Wang, Xiben, 1973- January 2000 (has links)
Stachybotrys elegans (Pidopl.) W. Gams is a destructive mycoparasite of the soilborne plant pathogen Rhizoctonia solani. It colonizes effectively all types of cells of R. solani, and is considered as an effective biological control agent (BCA). Monitoring the presence of this mycoparasite in the field trials requires the development of a reliable and sensitive diagnostic assay that is able to detect and differentiate the BCA from their target host. To achieve this, designed SCAR (sequenced characterized amplified regions) primers designated as SE-13F and SE-13R were generated from informative RAPD markers. They were tested in conventional PCR assays alone or in conjunction with the recently developed SCAR primers (SBU-177/336) designed for Rhizoctonia solani (Kuhn) on several types of DNA. These included DNA extracted from pure cultures, co-cultures of the BCA and the pathogen, plant tissue and several types of soils inoculated with both the BCA and the pathogen. Irrespective of the type of the biological samples from which the DNA was extracted, the primers SE-13F/SE-13R successfully amplified only S. elegans. No cross-reaction was observed when the primers were used to amplify DNA of other fungi, bacteria and plant tissues. Likewise, the primer pair SBU-177/336 detected only its target organism, i.e., R. solani. The detection limit using these primers on amplified DNA was as little as 1 pg DNA extracted from pure cultures of S. elegans, 100 pg DNA extracted from greenhouse soil and 33 pg DNA extracted from natural soil. This work is the first report on the development of SCAR markers for the BCA, S. elegans. These molecular markers offer not only an alternative diagnostic assay to conventional detection methods, but also the possibility of being used in ecological studies.

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