988 resultados para rubber tree (Hevea brasiliensis)


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Two new species of Zetzellia Oudemans, Z. agistzellia sp. n. and Z. quasagistemas sp. n., are described from rubber trees of northwestern São Paulo State, Brazil. Females have clear features of Zetzellia, whereas males resemble Agistemus in some characters. Immatures are also described. The discovery of these species raises some problems concerning generic concepts in Stigmaeidae. Since features of different genera are present in the same species, the authors suggest that the scope of those genera should be reviewed. Copyright © 2005 Magnolia Press.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Five commercial rubber tree clones in a clonal nursery were assessed for resistance to powdery mildew, as well as for the disease fluctuation and its correlation with the climate conditions in the study period. For this assessment, a diagrammatic scale was developed from 150 central leaflets randomly collected at different ages and attack levels. Validation of scale was done by five assessors. Results indicated that all clones showed susceptibility to the pathogen, and the attack was higher for younger leaflets. According to the climate data, mild temperatures and relative humidity below 60% favored the epidemic.

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Pós-graduação em Biociências - FCLAS

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Latex collected from natural rubber trees forming membranes can be used as biomaterials in several fields being the temperature a key parameter. Thermogravimetry (TG) coupled to Fourier transform infrared spectroscopy (FTIR) is a useful technique to investigate the thermal degradation of both latex and cast films (membranes), wich were obtained from Hevea brasiliensis (RRIM 600 clone) and used without stabilization. The membranes were prepared by casting the latex onto a glass substrate at 65 degrees C for 6 h. The thermal degradation was followed by FTIR spectra acquisition along the process, allowing the identification of the gaseous components evolved upon the thermal treatment. According to TG measurements, the main processes of thermal degradation of the latex and membranes occur at three temperature intervals for both.

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Pós-graduação em Biociências - FCLAS

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Premise of the study: Microsatellite primers were developed for Jatropha curcas (Euphorbiaceae), a tree species with large potential for biofuel production, to investigate its natural genetic diversity and mating system to facilitate the establishment of tree improvement and conservation programs. Methods and Results: Using a protocol for genomic library enrichment, 104 clones containing 195 repeat motifs were identified. Primer pairs were developed for 40 microsatellite loci and validated in 41 accessions of J. curcas from six provenances. Nine loci were polymorphic revealing from two to eight alleles per locus, and six primers were able to amplify alleles in the congeners J. podagrica, J. pohliana, and J. gossypifolia, but not in other Euphorbiaceae species, such as Hevea brasiliensis, Manihot esculenta, or Ricinus communis. Conclusions: The primers developed here revealed polymorphic loci that are suitable for genetic diversity and structure, mating system, and gene flow studies in J. curcas, and some congeners.

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El caucho natural y su proceso de transformación industrial es una cadena que presenta grandes potencialidades agroecológicas en el país, genera empleo rural productivo, construye capital y contribuye con el medio ambiente, razones que motivaron al autor a investigar los aspectos técnicos que el inversionista debe tener presente al momento de emprender un proyecto de reforestación comercial de caucho -- El caso de estudio se desarrolló para la microempresa Agroindustrias Villalonso, ubicada en la región heveícola del Magdalena Medio Santandereano, con el objetivo principal de analizar y abordar cada una de las etapas que constituyen un modelo de negocio, y proponerle a la microempresa, y demás interesados, cuáles son las mejores alternativas que deben desarrollarse para que un proyecto de este tipo tenga un resultado financiero positivo y por consiguiente un retorno favorable de la inversión -- La descripción y análisis de alternativas de todas las etapas que constituyen un modelo de negocio fueron desarrolladas con base en la metodología de Osterwalder & Pigneur, en el lienzo del modelo de negocio; esta metodología fue escogida como la más completa para este proyecto -- Del desarrollo de la investigación se evidenció que aunque el proyecto presenta características técnicas favorables, las condiciones macroeconómicas actuales, el entorno del mercado nacional y extranjero y los sistemas de explotación convencionales que elevan especialmente los costos en mano de obra, podrían poner en riesgo la viabilidad del mismo, a menos que la propuesta de valor se desarrolle a partir de los criterios y alternativas planteados en este trabajo

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Rubber tree is a very important crop in Thailand, representing an essential source of income for farmers. In the past two decades, rubber tree plantations have been greatly expanding in unfavorable areas, where climate conditions are difficult and soil fertility is very poor. To optimize latex yields, mineral fertilizers have been widely used. A better understanding of the roles of the biological compartment in soil fertility is essential to determine alternative management practices to sustain soil fertility and optimize latex yields. Arbuscular mycorrhizal fungi (AMF) are widely recognized as beneficial for plants, mainly through their role in improving plant nutrient uptake. The objective of this study was to assess the AMF populations in rubber tree plantations and the impact of both soil characteristics and plantation age on these communities. Our results showed that all rubber trees were highly colonized, regardless of the soil structure and nutrient contents. AMF colonization was not affected by the age of the trees, suggesting that maintaining the symbiosis is likely to be beneficial at all stages. A better understanding and management of the microbial communities would contribute to maintaining or restoring soil fertility, leading to a better tree growth and optimized latex yield.