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  1. AU="CARLOS PIMENTEL"
  2. AU="Castro, Anna"
  3. AU="Atkinson, Jeremy"
  4. AU="Ferreira, Henrique B"
  5. AU="Giulio Malucelli"
  6. AU=Fu Jia AU=Fu Jia

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  1. Artikel ; Online: Metabolismo de carbono de plantas cultivadas e o aumento de CO2 e de O3 atmosférico

    Carlos Pimentel

    Bragantia, Vol 70, Iss 1, Pp 1-

    situação e previsões

    2011  Band 12

    Abstract: A atividade de gases da atmosfera, principalmente os "Gases de Efeito Estufa" (GEE), como o vapor d'água, o gás carbônico, o metano, os óxidos de nitrogênio e o ozônio, passou a ser objeto de estudos devido ao seu aumento, causando as mudanças climáticas ...

    Abstract A atividade de gases da atmosfera, principalmente os "Gases de Efeito Estufa" (GEE), como o vapor d'água, o gás carbônico, o metano, os óxidos de nitrogênio e o ozônio, passou a ser objeto de estudos devido ao seu aumento, causando as mudanças climáticas globais, como o aumento da temperatura do ar, secas e outras. Além do gás carbônico, está havendo aumento da emissão de Compostos Orgânicos Voláteis (COV) na troposfera, além de óxidos de nitrogênio, que causam a produção de ozônio tóxico aos seres vivos. Este, o ozônio produzido em baixa altitude reduz a fotossíntese e produtividade de culturas sensíveis, como a soja e o algodão, culturas importantes no Brasil. O aumento substancial da concentração de gás carbônico na atmosfera, nos próximos anos, provavelmente causará aumento da fotossíntese e biomassa em plantas. Esse processo ocorrerá especialmente nas espécies arbóreas e gramíneas C3 e menos nas leguminosas e plantas C4. Entretanto, este aumento será menor que o previsto por estudos em ambiente controlado, segundo resultados de campo. Além disso, a maior concentração destes GEE na atmosfera causará aumento da temperatura do ar e redução da disponibilidade de água no solo, que podem anular o efeito benéfico e fertilizante do gás carbônico, especialmente quando associado ao efeito nocivo do aumento de ozônio na biosfera. Contudo, os estudos têm sido realizados em regiões temperadas, e pouco se sabe sobre a atividade do gás carbônico e ozônio, e seus efeitos sobre o metabolismo das plantas cultivadas, em regiões tropicais.
    Schlagwörter biomassa ; fotossíntese ; gases de efeito estufa ; ecofisiologia de plantas cultivadas ; Agriculture (General) ; S1-972
    Sprache Englisch
    Erscheinungsdatum 2011-01-01T00:00:00Z
    Verlag Instituto Agronômico de Campinas
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  2. Artikel ; Online: Cowpea

    Wedis Martins Ferreira / Gepatrik Rodrigues Lima / David Cabral Macedo / Murillo Freire Júnior / Carlos Pimentel

    Saudi Journal of Biological Sciences, Vol 29, Iss 12, Pp 103431- (2022)

    A low-cost quality protein source for food safety in marginal areas for agriculture

    2022  

    Abstract: Cowpea is a low-cost protein source for human nutrition for the world's impoverished regions. Therefore, the yield and total grain protein content (TGPC) of two modern commercials genotypes, Novaera and Gurguéia, and two traditional local genotypes, ... ...

    Abstract Cowpea is a low-cost protein source for human nutrition for the world's impoverished regions. Therefore, the yield and total grain protein content (TGPC) of two modern commercials genotypes, Novaera and Gurguéia, and two traditional local genotypes, Paulistinha and EPACE-10, were studied. Also, leaf area and dry weight, leaf soluble protein content, and chlorophyll a fluorescence, parameters related to photosynthetic capacity, were used to evaluate genotypes. Under optimal conditions, the yield of EPACE-10 and Paulistinha, with higher TGPC, was lower than for Gurguéia and Novaera, which showed lower TGPC. The four cowpea genotypes showed high lysine content and low methionine and cysteine. The results revealed a negative correlation between yield and TGPC. The modern commercial genotype Novaera showed a high yield with low TGPC but a higher globulin and albumin content than Gurguéia. Thus, it can be used in high-input agriculture. In contrast, the traditional local genotype EPACE-10, with high TGPC and higher amino acid content than Paulistinha, is indicated for low-input agriculture in marginal areas for food safety under climate changes.
    Schlagwörter Chlorophyll a fluorescence ; Grain amino acid content ; Grain protein quality ; Leaf area ; Leaf soluble protein content ; Vigna unguiculata (L.) Walp ; Biology (General) ; QH301-705.5
    Thema/Rubrik (Code) 580
    Sprache Englisch
    Erscheinungsdatum 2022-12-01T00:00:00Z
    Verlag Elsevier
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  3. Artikel ; Online: Protein, Phytate and Minerals in Grains of Commercial Cowpea Genotypes

    FABÍOLA V. GONÇALVES / LEONARDO O. MEDICI / MARCOS PAULO S. DA FONSECA / CARLOS PIMENTEL / SALETE A. GAZIOLA / RICARDO A. AZEVEDO

    Anais da Academia Brasileira de Ciências, Vol 92, Iss suppl

    2020  Band 1

    Abstract: Abstract The objective of this study was to investigate and characterize cowpea (Vigna unguiculata) genotypes for total grain protein content, storage protein fractions (globulin, albumin, prolamin, basic and acid glutelins), and phytate and minerals ... ...

    Abstract Abstract The objective of this study was to investigate and characterize cowpea (Vigna unguiculata) genotypes for total grain protein content, storage protein fractions (globulin, albumin, prolamin, basic and acid glutelins), and phytate and minerals contents. Eighteen cowpea genotypes were selected. Total grain protein content varied from 21.4% to 29.2%, for BRS Marataoã and Paulistinha genotypes, respectively. The variation in the concentration of each protein fraction was significant (P<0.05) only for glutelins (basic and acid). The genotypes studied exhibited great similarity in the PAGE electrophoretic profile of the grain protein fractions and also in the mineral content. BRS Paraguaçu genotype exhibited higher Zn content than thegenotypes that have been previously recommended for this characteristic. The lowest phytate grain content was observed in four of the 18 genotypes studied, which also exhibited high protein contents. Although the results did not converge to the selection of a few genotypes, some specific differences were detected that which may be further explored. Considering total grain protein, mineral and phytate contents, the genotype Paulistinha revealed a better balance unveiling high grain total protein content, low grain phytate content and more homogeneous mineral composition.
    Schlagwörter SDS-PAGE ; minerals ; phytate ; total protein ; Vigna unguiculata ; Science ; Q
    Thema/Rubrik (Code) 669
    Sprache Englisch
    Erscheinungsdatum 2020-07-01T00:00:00Z
    Verlag Academia Brasileira de Ciências
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  4. Artikel ; Online: RELAÇÕES HÍDRICAS EM DOIS HÍBRIDOS DE MILHO SOB DOIS CICLOS DE DEFICIÊNCIA HÍDRICA WATER RELATIONS IN TWO HYBRIDS OF CORN UNDER TWO CYCLES OF WATER STRESS

    CARLOS PIMENTEL

    Pesquisa Agropecuária Brasileira, Vol 34, Iss 11, Pp 2021-

    1999  Band 2027

    Abstract: Neste trabalho foram estudadas as relações hídricas de dois híbridos de milho (Zea mays L.), em casa de vegetação: o IAC 8222 (híbrido com tolerância ambiental) e o DINA 10 (híbrido comum); submetidos a um ou a dois ciclos de estresse, aos 30 e 46 DAP. O ...

    Abstract Neste trabalho foram estudadas as relações hídricas de dois híbridos de milho (Zea mays L.), em casa de vegetação: o IAC 8222 (híbrido com tolerância ambiental) e o DINA 10 (híbrido comum); submetidos a um ou a dois ciclos de estresse, aos 30 e 46 DAP. O IAC 8222 manteve o potencial hídrico de folha (psihf) superior ao do DINA no primeiro ciclo de estresse e no segundo ciclo, em plantas que sofreram os dois ciclos (com endurecimento), no sexto e último dia de deficiência hídrica, não havendo diferenças em relação ao conteúdo hídrico relativo (CHR) entre os híbridos. Houve um aumento da concentração de açúcares solúveis e de aminoácidos com a deficiência hídrica, sem diferenças entre os híbridos no primeiro ciclo de déficit hídrico, e com aumento significativo somente na concentração de aminoácidos no DINA 10 submetido aos dois ciclos, no último dia do segundo ciclo. A concentração de K+ não variou nem com os ciclos nem entre híbridos. Portanto, só houve diferenças na acumulação de solutos osmóticos entre os híbridos, quanto ao teor de aminoácidos no DINA 10 submetido aos dois ciclos, no segundo ciclo. Contudo, o IAC 8222 manteve o seu psihf alto, podendo ter promovido um ajuste do coeficiente de extensibilidade de parede, que foi acentuado com o endurecimento. A study was conducted to evaluate the water relations of two corn (Zea mays L.) hybrids in a greenhouse experiment: IAC 8222 (hybrid adapted to environmental stress) and DINA 10 (common hybrid), under one or two cycles of water stress applied at 30 and 46 days after sowing. During the first water deficit cycle, and at the second cycle for plants submitted to both cycles, the leaf water potential (psihf) of IAC 8222 was higher than the psihf of DINA 10, at the 6th and last day of water stress, with no difference for the relative water content (CHR) between the hybrids. The soluble sugars and amino acids accumulated during the water stress, but no differences between the hybrids were observed on the first cycle, and it was showed a difference on amino acids concentration for DINA 10 with hardening, on the 6th and last day of the second cycle. The K+ concentration did not change neither during the water stress nor between the hybrids. These results showed only differences on the capacity of solute accumulation of DINA 10, for amino acids on the second water stress cycle. However, IAC 8222 maintained a higher psihf, accentuated by the hardening. This response can be due to an adjustment in the coefficient of cell wall extensibility.
    Schlagwörter Zea mays ; potencial hídrico de folha ; conteúdo hídrico relativo ; leaf water potential ; relative water content ; Agriculture (General) ; S1-972
    Sprache Englisch
    Erscheinungsdatum 1999-11-01T00:00:00Z
    Verlag Embrapa Informação Tecnológica
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  5. Artikel ; Online: Estimation of interaction energy and contact stiffness in atomic-scale sliding on a model sodium chloride surface in ethanol

    Liron Agmon / Itai Shahar / Danny Yosufov / Carlos Pimentel / Carlos M. Pina / Enrico Gnecco / Ronen Berkovich

    Scientific Reports, Vol 8, Iss 1, Pp 1-

    2018  Band 8

    Abstract: Abstract Friction force microscopy (FFM) in aqueous environments has recently proven to be a very effective method for lattice-resolution imaging of crystal surfaces. Here we demonstrate the use of ethanol for similar measurements on water-soluble ... ...

    Abstract Abstract Friction force microscopy (FFM) in aqueous environments has recently proven to be a very effective method for lattice-resolution imaging of crystal surfaces. Here we demonstrate the use of ethanol for similar measurements on water-soluble materials. Lattice resolved frictional stick-slip traces of a cleaved NaCl(100) surface submerged in ethanol are compared with previous obtained FFM results in ultrahigh vacuum (UHV). We use the Prandtl-Tomlinson framework to estimate the amplitude of the corrugation potential and the contact stiffness. The surface potential amplitude scales with the applied normal loads are in good agreement with data obtained for NaCl measured under UHV conditions, but demonstrates deviations from the ideal periodic potential given by the Prandtl-Tomlinson model. An additional finding is that the use of ethanol allows us to explore higher load ranges without detectable evidence of surface wear. The contact stiffness does not vary significantly with the normal load up to 38 nN, while above it a sudden increase by almost one order of magnitude was observed. Comparing this to previous results suggests that considerable atom rearrangements may occur in the contact region, although the (100) surface structure is preserved by ethanol-assisted diffusion of Na and Cl ions.
    Schlagwörter Medicine ; R ; Science ; Q
    Thema/Rubrik (Code) 621
    Sprache Englisch
    Erscheinungsdatum 2018-03-01T00:00:00Z
    Verlag Nature Publishing Group
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  6. Artikel: Interaction of biological nitrogen fixation with sowing nitrogen fertilization on common bean in the two seasons of cultivation in Brazil

    Barros, Rodrigo Luiz Neves / Carlos Pimentel / Leandro Barbosa de Oliveira / Leonardo Oliveira Médici / Welliton Barros Magalhães

    Journal of plant nutrition. 2018 Apr. 3, v. 41, no. 6

    2018  

    Abstract: Sowing nitrogen (N) fertilization can limit biological nitrogen fixation (BNF) reducing common bean yield. The aim of this study was to evaluate the effect of sowing N fertilization plus inoculation on the growth and yield of plants in the two seasons of ...

    Abstract Sowing nitrogen (N) fertilization can limit biological nitrogen fixation (BNF) reducing common bean yield. The aim of this study was to evaluate the effect of sowing N fertilization plus inoculation on the growth and yield of plants in the two seasons of cultivation in Brazil. In the dry season, N fertilization and inoculation promoted a greater shoot dry weight and higher pod number and yield than only inoculated. In contrast, in the rainy season, this treatment promoted no increase in shoot dry weight and yield compared with the inoculated alone. The number of nodules was greater for the inoculated alone treatment, but nodule weight was not affected by N fertilization in either season. Therefore, sowing N fertilization and inoculation can be an agronomic practice to achieve a higher common bean yield in the dry season, while in the rainy season, the inoculation without N fertilization can support a high yield at a lower cost.
    Schlagwörter beans ; crop yield ; dry season ; fertilizer application ; nitrogen ; nitrogen fertilizers ; nitrogen fixation ; sowing ; wet season ; Brazil
    Sprache Englisch
    Erscheinungsverlauf 2018-0403
    Umfang p. 774-781.
    Erscheinungsort Taylor & Francis
    Dokumenttyp Artikel
    ZDB-ID 446190-3
    ISSN 1532-4087 ; 0190-4167
    ISSN (online) 1532-4087
    ISSN 0190-4167
    DOI 10.1080/01904167.2018.1426016
    Datenquelle NAL Katalog (AGRICOLA)

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  7. Artikel ; Online: COWPEA GROWTH AND YIELD IN SOLE CROP AND INTERCROPPED WITH MILLET

    LEANDRO BARBOSA DE OLIVEIRA / RODRIGO LUIZ NEVES BARROS / WELLITON BARROS DE MAGALHÃES / LEONARDO OLIVEIRA MEDICI / CARLOS PIMENTEL

    Revista Caatinga, Vol 30, Iss 1, Pp 53-

    2017  Band 58

    Abstract: The objective of this work was to evaluate the growth and yield of cowpea grains in different intercropping systems with millet, in wet and dry seasons. The experiments were performed in the experimental field of the Department of Plant Science of the ... ...

    Abstract The objective of this work was to evaluate the growth and yield of cowpea grains in different intercropping systems with millet, in wet and dry seasons. The experiments were performed in the experimental field of the Department of Plant Science of the Federal Rural University of Rio de Janeiro, Brazil, using a randomized block design with three replications and five treatments: T1- sole crop of millet; T2- sole crop of cowpea; T3- intercrop of millet (1 row) and cowpea (1 row) with 0.5 m between rows (1Mx1C-0.50); T4 - intercrop of millet (1 row) and cowpea (1 row) with 0.75 m between rows (1Mx1C-0.75); and T5 - intercrop of millet (1 row) and cowpea (2 rows) with 0.5 m between rows (1Mx2C-0.50). The cowpea shoot dry weight, root dry weight, number and dry weight of nodules, grain yield and 1000-grain weight, and the millet fresh weight, shoot dry weight, grain yield and 1000-grain weight were evaluated. The land-use efficiency index (LUE) showed significant differences in yield between the sole crop of cowpea and the intercropping system, with greater grain weight in the intercrop 1Mx2C-0.50. On the other hand, the intercrop 1Mx1C-0.75 was not recommended for the study conditions.
    Schlagwörter Agriculture ; S ; Biology (General) ; QH301-705.5
    Thema/Rubrik (Code) 630
    Sprache Englisch
    Erscheinungsdatum 2017-01-01T00:00:00Z
    Verlag Universidade Federal Rural do Semi-Árido
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  8. Artikel ; Online: Decomposição e ciclagem de nutrientes dos resíduos de quatro plantas de cobertura do solo Nutrient cycling and decomposition of crop residues of four cover crops for soil

    Michelle Barbosa Teixeira / Arcângelo Loss / Marcos Gervasio Pereira / Carlos Pimentel

    IDESIA, Vol 30, Iss 1, Pp 55-

    2012  Band 64

    Abstract: El mijo y el sorgo pueden ser utilizados como cultivos de protección para el suelo y el reciclado de nutrientes en suelos de baja fertilidad. Este estudio evaluó la descomposición y el ciclo de nutrientes en los residuos aéreos de cuatro plantas en un ... ...

    Abstract El mijo y el sorgo pueden ser utilizados como cultivos de protección para el suelo y el reciclado de nutrientes en suelos de baja fertilidad. Este estudio evaluó la descomposición y el ciclo de nutrientes en los residuos aéreos de cuatro plantas en un suelo arenoso, sin fertilizantes o riego. Los tratamientos consistieron en las plantas de mijo (cultivar ENA 2 BRS 1501), el sorgo (BRS 310) y malezas (MA). Las muestras conseguidas a los 87 días después de la siembra fueron estratificadas en hojas y tallos, colocadas y distribuidas en la superficie de las parcelas. La descomposición de la biomasa y la liberación de nutrientes fueron controladas mediante la acumulación de material, realizada 10, 20, 30, 60, 90 y 120 días después del corte. El mijo (ENA 2) acumuló la mayor cantidad de biomasa y materia seca en los tallos, mayor contenido de N, P y K en los residuos, seguido por sorgo, mijo (BRS 1501) y malezas. Con la excepción de K, hubo una rápida liberación de nutrientes por parte de las malezas MA, mientras que en el mijo (ENA 2) la liberación fue más gradual. BRS1501 y el BRS 310 mostraron valores intermedios y similares. La mayor materia seca de ENA 2 y su mayor tiempo de descomposición indican que se recomienda su uso como cultivo de cobertura y para reciclaje de nutrientes. Pearl millet and sorghum can be used as cover plants for soil and recycling of nutrients in soils of low fertility. This study evaluated the nutrient cycling and decomposition of crop residues of four cover crops in sandy soil, without fertilizer or irrigation. The treatments consisted of two pearl millet genotypes (cultivar ENA 2 and BRS1501), sorghum genotype BRS 310 and non- cultivated plants (weeds - VE). Samples of shoots, stratified into leaves and stems collected 87 days after planting were placed in bags and distributed on the surface of the plots. The dry matter decomposition and nutrient release were monitored through collection of material from the bags 10, 20, 30, 60, 90 and 120 days after cutting. The ENA 2 showed the greatest amounts of biomass and dry weight of stems and higher levels of N, P and K in its remaining detritus, followed by sorghum, BRS 1501 and VE. With the exception of K, there was a rapid release of all nutrients by VE, while the ENA 2 nutrient release was more gradual, and was intermediate and similar for BRS 1501 and sorghum. The greater dry weight and slower decomposition of cultivar ENA 2 make it the recommended genotype for use as soil cover and nutrient recycling.
    Schlagwörter acumulación de nutrientes ; la biomasa ; mijo ; sorgo ; C/N ; nutrient accumulation ; biomass ; pearl millet ; grain sorghum ; C/N relationship ; Agriculture (General) ; S1-972 ; Agriculture ; S ; DOAJ:Agriculture (General) ; DOAJ:Agriculture and Food Sciences
    Sprache Spanisch
    Erscheinungsdatum 2012-04-01T00:00:00Z
    Verlag Universidad de Tarapacá. Facultad de Ciencias Agronómicas
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  9. Artikel ; Online: Decomposição e liberação de nutrientes da parte aérea de plantas de milheto e sorgo

    Michelle Barbosa Teixeira / Arcângelo Loss / Marcos Gervasio Pereira / Carlos Pimentel

    Revista Brasileira de Ciência do Solo, Vol 35, Iss 3, Pp 867-

    2011  Band 876

    Abstract: O milheto pode ser usado como planta de cobertura para o solo e recicladora de nutrientes em solos de baixa fertilidade natural. O objetivo deste trabalho foi avaliar a taxa de decomposição e a liberação de nutrientes pela parte aérea de plantas de ... ...

    Abstract O milheto pode ser usado como planta de cobertura para o solo e recicladora de nutrientes em solos de baixa fertilidade natural. O objetivo deste trabalho foi avaliar a taxa de decomposição e a liberação de nutrientes pela parte aérea de plantas de milheto e sorgo deixada sobre o solo. Os tratamentos consistiram de plantas de milheto, com as cultivares pérola ENA 2 e BRS 1501, e plantas de sorgo do híbrido BRS 310. Após o corte, no final do ciclo, amostras da parte aérea foram acondicionadas em bolsas de decomposição distribuídas na superfície das parcelas. A decomposição da matéria seca e a liberação de nutrientes foram monitoradas por meio de coletas dos resíduos, contidos nas bolsas de decomposição, realizadas aos 10, 20, 30, 60, 90 e 120 dias após o corte das plantas. A massa do milheto ENA 2 apresentou menor velocidade de decomposição, com t½ (tempo de meia-vida) =112 dias, sendo maior que a do BRS 1501 (98 dias) e do sorgo (96 dias). Houve rápida liberação de N pelo sorgo, enquanto nas cultivares de milheto a liberação foi gradativa, sendo o K e o Mg os nutrientes liberados mais rapidamente em todas as plantas de cobertura utilizadas. Os resultados indicam que a cultivar de milheto ENA 2 apresenta maior t½ para matéria seca, sendo mais favorável para uso em áreas de clima tropical, como planta de cobertura e recicladora de nutrientes, com liberação gradativa de N, P e Ca para o solo.
    Schlagwörter biomassa vegetal ; cultivar ENA 2 ; fertilidade do solo ; Agriculture (General) ; S1-972
    Sprache Englisch
    Erscheinungsdatum 2011-06-01T00:00:00Z
    Verlag Sociedade Brasileira de Ciência do Solo
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  10. Artikel ; Online: Limitations to photosynthesis at different temperatures in the leaves of Citrus limon Análise in vivo das limitações da fotossíntese, sob diferentes temperaturas, em folhas de Citrus limon

    Carlos Pimentel / Carl Bernacchi / Steve Long

    Brazilian Journal of Plant Physiology, Vol 19, Iss 2, Pp 141-

    2007  Band 147

    Abstract: The response of CO2 assimilation rate (A) to the intercellular partial pressure of CO2 (Ci) was measured on intact lemon leaves over a range of temperatures (10 to 40ºC). The A/Ci response shows how change in the leaf temperature alters the activity of ... ...

    Abstract The response of CO2 assimilation rate (A) to the intercellular partial pressure of CO2 (Ci) was measured on intact lemon leaves over a range of temperatures (10 to 40ºC). The A/Ci response shows how change in the leaf temperature alters the activity of ribulose-1,5-bisphosphate (RuBP) carboxylase-oxygenase (Rubisco) and RuBP regeneration via electron transport. The rate of A reached a maximum of 7.9 to 8.9 µmol m-2 s-1 between 25 and 30ºC, while dark respiration (Rd) increased with temperature from 0.4 µmol m-2 s-1 at 10ºC to 1.4 µmol m-2 s-1 at 40ºC. The maximum rates of carboxylation (Vc,max) and the maximum rates of electron transport (Jmax) both increased over this temperature range from 7.5 to 142 µmol m-2 s-1 and from 23.5 to 152 µmol m-2 s-1, respectively. These temperature responses showed that A can be limited by either process depending on the leaf temperature, when Ci or stomatal conductance are not limiting. The decrease in A associated with higher temperatures is in part a response to the greater increase in the rate of oxygenation of RuBP compared with carboxylation and Rd at higher temperatures. Although A can in theory be limited at higher Ci by the rate of triose-phosphate utilization, this limitation was not evident in lemon leaves. A resposta da taxa de assimilação de CO2 (A) à pressão parcial de CO2 (Ci) foi medida em folhas intactas de limão cravo, numa ampla faixa de temperaturas (10 to 40ºC). A variação na curva A/Ci mostrou como as mudanças na temperatura foliar alteram a atividade da ribulose-1,5-bisfosfato (RuBP) carboxilase-oxigenase (Rubisco) e a regeneração da RuBP, via transporte de elétrons. O valor máximo de A obtido foi de 7.9 a 8.9 µmol m-2 s-1, entre 25 e 30ºC, enquanto a respiração mitocondrial (Rd) aumentou com a temperatura, de 0.4 µmol m-2 s-1 a 10ºC até 1.4 µmol m-2 s-1, a 40ºC. A taxa máxima de carboxilação (Vc,max) e a taxa máxima de transporte de elétrons (Jmax) aumentaram naquela faixa de temperatura, de 7.5 a 142 µmol m-2 s-1, e de 23.5 a 152 µmol m-2 s-1, respectivamente. A redução em A associada às altas temperaturas é, em parte, uma resposta ao maior aumento na taxa de oxigenação da RuBP, comparada à taxa de carboxilação, e de Rd sob altas temperaturas. Apesar de A poder ser, em teoria, limitada sob elevada Ci pela taxa de utilização de triose-fosfato, essa limitação não foi evidente nas folhas analisadas.
    Schlagwörter curvas A/Ci ; limão cravo ; trocas gasosas ; A/Ci curves ; gas exchange ; lemon ; Botany ; QK1-989 ; Science ; Q ; DOAJ:Botany ; DOAJ:Biology ; DOAJ:Biology and Life Sciences ; Plant culture ; SB1-1110 ; Agriculture ; S ; DOAJ:Plant Sciences ; DOAJ:Agriculture and Food Sciences
    Sprache Englisch
    Erscheinungsdatum 2007-06-01T00:00:00Z
    Verlag Brazilian Journal of Plant Physiology
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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