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Registro Completo |
Biblioteca(s): |
Embrapa Florestas. |
Data corrente: |
03/02/2009 |
Data da última atualização: |
25/02/2015 |
Tipo da produção científica: |
Artigo em Periódico Indexado |
Autoria: |
MAIA, C. M. B. F.; PICCOLO, A.; MANGRICH, A. S. |
Afiliação: |
Claudia Maria Branco Freitas Maia, Embrapa Florestas; Alessandro Piccolo, Università di Napoli Federico II; Antonio S. Mangrich, UFPR. |
Título: |
Molecular size distribution of compost-derived humates as a function of concentration and different counterions. |
Ano de publicação: |
2008 |
Fonte/Imprenta: |
Chemosphere, v. 73, n. 8, p. 1162-1166, 2008. |
DOI: |
10.1016/j.chemosphere.2008.07.069 |
Idioma: |
Inglês |
Conteúdo: |
Conformational changes in the structures of humic acids (HA) extracted from compost with varying degrees of maturity were monitored by high performance size exclusion chromatography (HPSEC). The molecular size distribution of HA was compared in solutions containing sodium or ammonium counterions at pH 7 and pH 4.5. These findings indicate that the humates’ molecular size depended not only on the nature of the counterions but also on their concentration in the solution. The physicochemical nature of sodium counterions determined smaller molecular sizes than those of the more hydrated ammonium counterions, at low concentrations of humates. Conversely, at higher humate concentrations, the more compact conformation of sodium humates produced larger molecular sizes than those of ammonium humates due to the aggregation of more hydrophobic surfaces in the sodium humates. Composting led to the degradation of labile microbial components with accumulation of hydrophobic constituents. This caused self-association of hydrophobic compounds into humic superstructures of larger molecular size over composting time. At lower pH, changes in conformational stability by the addition of acetic acid to humate solutions were explained by the supramolecular model of humified organic matter. |
Palavras-Chave: |
Compost; Composto; Estrutura supramolecular; HPSEC; Molecular size; Substância húmica; Supramolecular structure; Tamanho molecular. |
Thesaurus Nal: |
humic substances. |
Categoria do assunto: |
-- |
Marc: |
LEADER 02099naa a2200265 a 4500 001 1315461 005 2015-02-25 008 2008 bl uuuu u00u1 u #d 024 7 $a10.1016/j.chemosphere.2008.07.069$2DOI 100 1 $aMAIA, C. M. B. F. 245 $aMolecular size distribution of compost-derived humates as a function of concentration and different counterions.$h[electronic resource] 260 $c2008 520 $aConformational changes in the structures of humic acids (HA) extracted from compost with varying degrees of maturity were monitored by high performance size exclusion chromatography (HPSEC). The molecular size distribution of HA was compared in solutions containing sodium or ammonium counterions at pH 7 and pH 4.5. These findings indicate that the humates’ molecular size depended not only on the nature of the counterions but also on their concentration in the solution. The physicochemical nature of sodium counterions determined smaller molecular sizes than those of the more hydrated ammonium counterions, at low concentrations of humates. Conversely, at higher humate concentrations, the more compact conformation of sodium humates produced larger molecular sizes than those of ammonium humates due to the aggregation of more hydrophobic surfaces in the sodium humates. Composting led to the degradation of labile microbial components with accumulation of hydrophobic constituents. This caused self-association of hydrophobic compounds into humic superstructures of larger molecular size over composting time. At lower pH, changes in conformational stability by the addition of acetic acid to humate solutions were explained by the supramolecular model of humified organic matter. 650 $ahumic substances 653 $aCompost 653 $aComposto 653 $aEstrutura supramolecular 653 $aHPSEC 653 $aMolecular size 653 $aSubstância húmica 653 $aSupramolecular structure 653 $aTamanho molecular 700 1 $aPICCOLO, A. 700 1 $aMANGRICH, A. S. 773 $tChemosphere$gv. 73, n. 8, p. 1162-1166, 2008.
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Embrapa Florestas (CNPF) |
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Biblioteca(s): |
Embrapa Soja. |
Data corrente: |
13/07/2017 |
Data da última atualização: |
01/12/2017 |
Tipo da produção científica: |
Artigo em Anais de Congresso |
Autoria: |
ADEGAS, F. S.; GAZZIERO, D. L. P.; VOLL, E.; VARGAS, L. |
Afiliação: |
FERNANDO STORNIOLO ADEGAS, CNPSO; DIONISIO LUIZ PISA GAZZIERO, CNPSO; ELEMAR VOLL, CNPSO; LEANDRO VARGAS, CNPT. |
Título: |
Monitoramento de digitaria insularis resistente ao herbicida gliflosato no Estado de São Paulo. |
Ano de publicação: |
2017 |
Fonte/Imprenta: |
In: REUNIÃO DE PESQUISA DE SOJA, 36., 2017, Londrina, PR. Resumos expandidos... Londrina: Embrapa Soja, 2017. p. 209-211.(Embrapa Soja. Documentos, 388). Editado por Alvadi Antonio Balbinot Junior, Fernando Augusto Henning, Regina Maria Villas Bôas de Campos Leite. |
Idioma: |
Português |
Palavras-Chave: |
Glifosato. |
Thesagro: |
Erva daninha; Resistência; Soja. |
Thesaurus NAL: |
Soybeans; Weeds. |
Categoria do assunto: |
F Plantas e Produtos de Origem Vegetal |
URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/161734/1/209.pdf
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Marc: |
LEADER 00817nam a2200205 a 4500 001 2072643 005 2017-12-01 008 2017 bl uuuu u00u1 u #d 100 1 $aADEGAS, F. S. 245 $aMonitoramento de digitaria insularis resistente ao herbicida gliflosato no Estado de São Paulo.$h[electronic resource] 260 $aIn: REUNIÃO DE PESQUISA DE SOJA, 36., 2017, Londrina, PR. Resumos expandidos... Londrina: Embrapa Soja, 2017. p. 209-211.(Embrapa Soja. Documentos, 388). Editado por Alvadi Antonio Balbinot Junior, Fernando Augusto Henning, Regina Maria Villas Bôas de Campos Leite.$c2017 650 $aSoybeans 650 $aWeeds 650 $aErva daninha 650 $aResistência 650 $aSoja 653 $aGlifosato 700 1 $aGAZZIERO, D. L. P. 700 1 $aVOLL, E. 700 1 $aVARGAS, L.
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