13c Isotopic Discrimination
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Interação entre os estresses de nitrogênio e disponibilidade hídrica no fracionamento isotópico de 13C e na produtividade em soqueira de cana-de-açúcar / Interaction between nitrogen and water availability over isotopic discrimination of 13C and ratoon sugarcane production
The sugarcane crop has an important contribution in sub tropical and tropical regions around the world, which Brazil the major producer of sugarcane crop, sugar and ethanol. However, the sugarcane yield is still very low in many regions of this country, mainly due to water stress and nitrogen supply. Understand the loss sugarcane production related with wate
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/05/2012
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2. Sequestro e discriminação isotópica de carbono em sistemas agrossilvipastoris / Carbon sequestation and isotopic discrimination in agrosilvopasture
O estudo foi realizado com o objetivo de avaliar o efeito de diferentes sistemas de uso da terra no estoque e na dinâmica do carbono orgânico do solo (COS). Para isso foram coletadas amostras de solo em seis diferentes sistemas de uso da terra na Fazenda Riacho, pertencente à Votorantim Siderurgia Unidade Agroflorestal-, no município de Vazante, MG. Os s
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/05/2010
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3. Transferência do carbono de resíduos da colheita de eucalipto para frações da matéria orgânica do solo / Carbon transference from eucalypt harvest residues to soil organic matter fractions
Eucalypt plantation areas in Brazil have increased continuously over the years. The practice of removing more lignified material, such as bark and branches, from the ground after wood harvesting in eucalypt forests may prevent the stabilization of carbon (C) in recalcitrant fractions of soil organic matter (SOM). The recalcitrance of such organic fractions i
Publicado em: 2008
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4. Caracterização dos vinhos Merlot e Cabernet Sauvignon da serra gaúcha através de determinação das razões isotópicas 13C/12C e 18O/16O
In this work, wines provided by micro-winemakings of the variety Merlot and Cabernet Sauvignon of the sub-regions of Pinto Bandeira, Vale dos Vinhedos, Nova Pádua and Monte Belo do Sul in the 2005 and 2006 harvest have been studied. It has been established the isotopic ratios 13C/12C of the ethanol and 18O/16O of the water and ethanol, seeking for a possibl
Publicado em: 2006
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5. Carbon Isotopic Fractionation Does Not Occur during Dark Respiration in C3 and C4 Plants.
The magnitude of possible carbon isotopic fractionation during dark respiration was investigated with isolated mesophyll cells from mature leaves of common bean (Phaseolus vulgaris L.), a C3 plant, and corn (Zea mays L.), a C4 plant. Mesophyll protoplasts were extracted from greenhouse-grown leaves and incubated in culture solutions containing different carb
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6. Stable Carbon Isotope Fractionation by Methanosarcina barkeri during Methanogenesis from Acetate, Methanol, or Carbon Dioxide-Hydrogen
Methanosarcina barkeri was cultured on methanol, H2-CO2, and acetate, and the 13C/12C ratios of the substrates and the methane produced from them were determined. The discrimination against 13C in methane relative to substrate decreased in the order methanol > CO2 > acetate. The isotopic fractionation for methane derived from acetate was only one-third of th
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7. Bleaching in reef corals: Physiological and stable isotopic responses
During the late summer to fall of 1987, Caribbean reef corals experienced an intense and widespread discoloration event described as bleaching. Contrary to initial predictions, most bleached corals did not die. However, energy input from zooxanthellae decreased, as estimated from: (i) δ13C values, a measure of the discrimination against 13C in 12C/13C assim
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8. Natural Abundance Carbon Isotope Composition of Isoprene Reflects Incomplete Coupling between Isoprene Synthesis and Photosynthetic Carbon Flow
Isoprene emission from leaves is dynamically coupled to photosynthesis through the use of primary and recent photosynthate in the chloroplast. However, natural abundance carbon isotope composition (δ13C) measurements in myrtle (Myrtus communis), buckthorn (Rhamnus alaternus), and velvet bean (Mucuna pruriens) showed that only 72% to 91% of the variations in
American Society of Plant Biologists.
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9. Internal Conductance to CO2 Diffusion and C18OO Discrimination in C3 Leaves1
18O discrimination in CO2 stems from the oxygen exchange between 18O-enriched water and CO2 in the chloroplast, a process catalyzed by carbonic anhydrase (CA). A proportion of this 18O-labeled CO2 escapes back to the atmosphere, resulting in an effective discrimination against C18OO during photosynthesis (Δ18O). By constraining the δ18O of chloroplast wate
American Society of Plant Physiologists.
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10. Stable Carbon Isotope Fractionation by Sulfate-Reducing Bacteria
Biogeochemical transformations occurring in the anoxic zones of stratified sedimentary microbial communities can profoundly influence the isotopic and organic signatures preserved in the fossil record. Accordingly, we have determined carbon isotope discrimination that is associated with both heterotrophic and lithotrophic growth of pure cultures of sulfate-r
American Society for Microbiology.
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11. Water Relations Link Carbon and Oxygen Isotope Discrimination to Phloem Sap Sugar Concentration in Eucalyptus globulus
A strong correlation was previously observed between carbon isotope discrimination (Δ13C) of phloem sap sugars and phloem sap sugar concentration in the phloem-bleeding tree Eucalyptus globulus Labill. (J. Pate, E. Shedley, D. Arthur, M. Adams [1998] Oecologia 117: 312–322). We hypothesized that correspondence between these two parameters results from cov
American Society of Plant Biologists.