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Registro Completo |
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Biblioteca(s): |
Embrapa Florestas. |
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Data corrente: |
18/04/2000 |
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Data da última atualização: |
24/03/2026 |
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Autoria: |
WALKER, D. A.; OSMOND, C. B. |
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Título: |
Measurement of photosynthesis in vivo with a leaf disc electrode: correlations between light dependence of steady-state photosynthetic O2 evolution and chlorophyll a fluorescence transients. |
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Ano de publicação: |
1986 |
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Fonte/Imprenta: |
Proceedings of The Royal Society of London, Serie B. Biological Sciences, v. 227, p. 267-280, 1986. |
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Idioma: |
Inglês |
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Conteúdo: |
The application of a leaf disc electrode to the measurement of the quantum yield of photosynthetic oxygen evolution (in saturating carbon dioxide concentrations) is described. The technique was also used to characterize the light-saturation curves for photosynthesis in leaves of spinach plants grown in relatively low (`shade') and high (`sun') light intensities. It was found that the flux of a blue excitation light required to elicit oscillations in chlorophyll a fluorescence corresponded, approximately, to the flux of (white) light required to saturate photosynthetic oxygen evolution. The requirement was higher for leaves of sun-grown plants (approximately 800 μ mol m-2 s-1) than for shade-grown plants (approximately 200 μ mol m-2 s-1). Brief pretreatment of leaf discs from sun-grown plants with D-mannose did not change the quantum yield, but lowered the light saturated rate and the photon flux density required to saturate photosynthesis. Oscillations in fluorescence could then be observed at lower fluxes of blue excitation light, similar to those required by leaves from shade-grown plants. Photoinhibition of shade-grown plants (exposed to full sunlight for 5 h) reduced quantum yield and increased the light flux required for saturation of photosynthesis. Oscillations in fluorescence, normally observed at low fluxes of blue light in these leaves, could not be detected after photoinhibition. These correlations are interpreted and applications of the techniques described are discussed. MenosThe application of a leaf disc electrode to the measurement of the quantum yield of photosynthetic oxygen evolution (in saturating carbon dioxide concentrations) is described. The technique was also used to characterize the light-saturation curves for photosynthesis in leaves of spinach plants grown in relatively low (`shade') and high (`sun') light intensities. It was found that the flux of a blue excitation light required to elicit oscillations in chlorophyll a fluorescence corresponded, approximately, to the flux of (white) light required to saturate photosynthetic oxygen evolution. The requirement was higher for leaves of sun-grown plants (approximately 800 μ mol m-2 s-1) than for shade-grown plants (approximately 200 μ mol m-2 s-1). Brief pretreatment of leaf discs from sun-grown plants with D-mannose did not change the quantum yield, but lowered the light saturated rate and the photon flux density required to saturate photosynthesis. Oscillations in fluorescence could then be observed at lower fluxes of blue excitation light, similar to those required by leaves from shade-grown plants. Photoinhibition of shade-grown plants (exposed to full sunlight for 5 h) reduced quantum yield and increased the light flux required for saturation of photosynthesis. Oscillations in fluorescence, normally observed at low fluxes of blue light in these leaves, could not be detected after photoinhibition. These correlations are interpreted and applications of the techniques described are d... Mostrar Tudo |
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Palavras-Chave: |
Chlorophylls; Luz; Spinacea oleracea. |
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Thesagro: |
Clorofila; Folha; Fotossíntese. |
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Thesaurus Nal: |
Leaves; Light; Photosynthesis. |
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Categoria do assunto: |
S Ciências Biológicas |
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Marc: |
LEADER 02298nam a2200229 a 4500
001 1303872
005 2026-03-24
008 1986 bl uuuu u00u1 u #d
100 1 $aWALKER, D. A.
245 $aMeasurement of photosynthesis in vivo with a leaf disc electrode$bcorrelations between light dependence of steady-state photosynthetic O2 evolution and chlorophyll a fluorescence transients.$h[electronic resource]
260 $aProceedings of The Royal Society of London, Serie B. Biological Sciences, v. 227, p. 267-280, 1986.$c1986
520 $aThe application of a leaf disc electrode to the measurement of the quantum yield of photosynthetic oxygen evolution (in saturating carbon dioxide concentrations) is described. The technique was also used to characterize the light-saturation curves for photosynthesis in leaves of spinach plants grown in relatively low (`shade') and high (`sun') light intensities. It was found that the flux of a blue excitation light required to elicit oscillations in chlorophyll a fluorescence corresponded, approximately, to the flux of (white) light required to saturate photosynthetic oxygen evolution. The requirement was higher for leaves of sun-grown plants (approximately 800 μ mol m-2 s-1) than for shade-grown plants (approximately 200 μ mol m-2 s-1). Brief pretreatment of leaf discs from sun-grown plants with D-mannose did not change the quantum yield, but lowered the light saturated rate and the photon flux density required to saturate photosynthesis. Oscillations in fluorescence could then be observed at lower fluxes of blue excitation light, similar to those required by leaves from shade-grown plants. Photoinhibition of shade-grown plants (exposed to full sunlight for 5 h) reduced quantum yield and increased the light flux required for saturation of photosynthesis. Oscillations in fluorescence, normally observed at low fluxes of blue light in these leaves, could not be detected after photoinhibition. These correlations are interpreted and applications of the techniques described are discussed.
650 $aLeaves
650 $aLight
650 $aPhotosynthesis
650 $aClorofila
650 $aFolha
650 $aFotossíntese
653 $aChlorophylls
653 $aLuz
653 $aSpinacea oleracea
700 1 $aOSMOND, C. B.
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| Registros recuperados : 3 | |
| 2. |  | MATTOS, M. A. A.; OLIVEIRA, J. V.; HAJI, F. N. P.; LIMA, M. F.; COSTA, N. D. Eficácia de estratégias com agroquímicos no controle de Bemisia argentifolii Bellows & Perring (Hemiptera: Aleyrodidae) em tomate, no Submédio do Vale do São Francisco. In: CONGRESSO BRASILEIRO DE ENTOMOLOGIA, 19., 2002, Manaus. Resumos... Manaus: INPA/SEB, 2002. p. 112.| Tipo: Resumo em Anais de Congresso |
| Biblioteca(s): Embrapa Semiárido. |
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| 3. | | OLIVEIRA, J. V.; MATTOS, M. A. A.; HAJI, F. N. P.; LIMA, M. F.; COSTA, N. D. Utilização de estratégias com agroquímicos no controle de ovos, ninfas e adultos de Bemisia argentifolii Bellows e Perring (Hemiptera: Aleyrodidae) em tomate, no Submédio do Vale do São Francisco. Pesticidas: Revista de Ecotoxicologia e Meio Ambiente, v. 13, p. 59-72, jan./dez. 2003.| Tipo: Artigo em Periódico Indexado | Circulação/Nível: Nacional - B |
| Biblioteca(s): Embrapa Semiárido. |
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| Registros recuperados : 3 | |
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