Variações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábica
Autor(a) principal: | |
---|---|
Data de Publicação: | 2008 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | LOCUS Repositório Institucional da UFV |
Texto Completo: | http://locus.ufv.br/handle/123456789/4292 |
Resumo: | This study was carried out in order to examine (i) the diurnal changes in photosynthesis rates under low atmospheric evaporative demand, and (ii) the relationship between the rate of net photosynthesis (A) and carbon (C) metabolism in experimentally-manipulated branches through girdling. Two experiments were separately conducted and so analyzed. In both experiments, plants of arabica coffee (Coffea arabica L.) were grown in 12-L pots during approximately eight months. Then, gas exchanges (measured using an infrared gas analyzer), the rate of uptake of 14CO2 and the partitioning of the recently fixed 14C through the major photosynthetic routes were analyzed; leaf material was also harvested for biochemical assays. In Experiment I, plants were grown in a greenhouse under semi-controlled conditions (diurnal values of vapor pressure deficit, VPD, ranging from 1.0 to 1.6 kPa). There was a decrease (20%) in A paralleling a reduction (35%) in stomatal conductance (gs) at 16:00 h as compared with the values of these traits obtained at 08:00 and 12:00 h. The narrow diurnal fluctuations in A were apparently coupled with the maintenance of low VPD throughout the day. Simple and canonical correlations evidenced a lack of feedback inhibition to photosynthesis, a fact further supported by the (i) lack of diurnal changes in carbohydrate and amino acid levels and (ii) unchanging rate of 14CO2 uptake and the partitioning of the recently fixed 14C during the day. In addition, the activity of ADP-glucose pyrophosphorylase and the initial and total activities of Rubisco (as well as its activation state) did not change during the day. In fact, diurnal variations in A were largely explained by diffusive limitations. In Experiment II, gas exchange was measured at 08:00 h during 11 days in girdled and non-girdled (control) branches. There was a remarkable decrease in A and especially in gs. In girdled branches, starch levels increased by 271% and 203%, respectively at the 4th and 10th days after applying the treatments. The hexose-to-amino acid ratio increased in girdled branches at the 10th day of girdling, but the concentrations of other soluble sugars and amino acids did no change in response to the treatments, as also did the activity of ADP-glucose pyrophosphorylase and the initial and total activities of Rubisco. Moreover, the potential photosynthetic capacity also remained unchanged after girdling, suggesting that changes in A were marginally affected, if so, by biochemical constraints to the photosynthetic machinery. As in Experiment I, changes in A were largely explained by diffusive limitations. In summary, it is proposed that diurnal oscillations in A during the day, as well as between leaves from girdled and non-girdled branches were merely a consequence from diffusive, rather than from biochemical, limitations to photosynthesis. |
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Batista, Karine Diashttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4774216J5Loureiro, Marcelo Ehlershttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4780851Y3Ventrella, Marília Continhttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4763436A2Damatta, Fábio Murilohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4784185Y9Barros, Raimundo Santoshttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787859T6Ronchi, Cláudio Pagottohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4767872T7Pinheiro, Hugo Alveshttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792911A52015-03-26T13:36:36Z2008-09-082015-03-26T13:36:36Z2008-02-26BATISTA, Karine Dias. Diurnal changes in photosynthesis and effects of branch girdling on photosynthesis and carbon metabolism in arabica coffee. 2008. 43 f. Dissertação (Mestrado em Controle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superiores) - Universidade Federal de Viçosa, Viçosa, 2008.http://locus.ufv.br/handle/123456789/4292This study was carried out in order to examine (i) the diurnal changes in photosynthesis rates under low atmospheric evaporative demand, and (ii) the relationship between the rate of net photosynthesis (A) and carbon (C) metabolism in experimentally-manipulated branches through girdling. Two experiments were separately conducted and so analyzed. In both experiments, plants of arabica coffee (Coffea arabica L.) were grown in 12-L pots during approximately eight months. Then, gas exchanges (measured using an infrared gas analyzer), the rate of uptake of 14CO2 and the partitioning of the recently fixed 14C through the major photosynthetic routes were analyzed; leaf material was also harvested for biochemical assays. In Experiment I, plants were grown in a greenhouse under semi-controlled conditions (diurnal values of vapor pressure deficit, VPD, ranging from 1.0 to 1.6 kPa). There was a decrease (20%) in A paralleling a reduction (35%) in stomatal conductance (gs) at 16:00 h as compared with the values of these traits obtained at 08:00 and 12:00 h. The narrow diurnal fluctuations in A were apparently coupled with the maintenance of low VPD throughout the day. Simple and canonical correlations evidenced a lack of feedback inhibition to photosynthesis, a fact further supported by the (i) lack of diurnal changes in carbohydrate and amino acid levels and (ii) unchanging rate of 14CO2 uptake and the partitioning of the recently fixed 14C during the day. In addition, the activity of ADP-glucose pyrophosphorylase and the initial and total activities of Rubisco (as well as its activation state) did not change during the day. In fact, diurnal variations in A were largely explained by diffusive limitations. In Experiment II, gas exchange was measured at 08:00 h during 11 days in girdled and non-girdled (control) branches. There was a remarkable decrease in A and especially in gs. In girdled branches, starch levels increased by 271% and 203%, respectively at the 4th and 10th days after applying the treatments. The hexose-to-amino acid ratio increased in girdled branches at the 10th day of girdling, but the concentrations of other soluble sugars and amino acids did no change in response to the treatments, as also did the activity of ADP-glucose pyrophosphorylase and the initial and total activities of Rubisco. Moreover, the potential photosynthetic capacity also remained unchanged after girdling, suggesting that changes in A were marginally affected, if so, by biochemical constraints to the photosynthetic machinery. As in Experiment I, changes in A were largely explained by diffusive limitations. In summary, it is proposed that diurnal oscillations in A during the day, as well as between leaves from girdled and non-girdled branches were merely a consequence from diffusive, rather than from biochemical, limitations to photosynthesis.O presente estudo foi conduzido procurando-se analisar (i) as variações diurnas da fotossíntese numa condição de baixa demanda evaporativa e (ii) as relações entre A e o metabolismo do carbono em ramos experimentalmente manipulados, via anelamento. Foram conduzidos dois experimentos isoladamente e analisados como tal. Em ambos, plantas de café arábica (Coffea arabica L.) foram cultivadas em vasos de doze litros, por aproximadamente oito meses, quando, então, foram avaliadas as trocas gasosas (usando-se de um analisador de gases a infravermelho), a taxa de fixação de 14CO2 e a partição de [14C]-assimilados entre as principais rotas biossintéticas associadas à fotossíntese; adicionalmente, foi coletado material foliar para análises bioquímicas posteriores. No primeiro experimento, as plantas foram cultivadas em uma casa de vegetação sob condições semi-controladas, com valores diurnos do déficit de pressão de vapor (DPV) variando de 1,0 a 1,6 kPa. Houve uma redução (20%) da taxa de fotossíntese líquida (A) em paralelo a um decréscimo (35%) na condutância estomática (gs), às 16:00 h, em comparação com os valores dessas variáveis obtidos às 08:00 e 12:00 h. As pequenas flutuações diurnas de A parecem ter sido resultantes da manutenção artificial do DPV em níveis relativamente baixos. As correlações simples e canônicas sugeriram que não houve retroinibição da fotossíntese, fato suportado pela ausência de variações diurnas nas concentrações de carboidratos e aminoácidos e pela constância da taxa de absorção de 14CO2 e da partição de [14C]-assimilados, ao longo do dia. Em adição, não se observou aumento na atividade da AGPase, tampouco decréscimo nas atividades inicial e total e no estado de ativação da Rubisco ao final da tarde. Com efeito, as variações diurnas em A foram largamente explicáveis por limitações difusivas à fotossíntese. No segundo experimento, as trocas gasosas foram analisadas ao longo de onze dias após o anelamento dos ramos, às 08:00 h, observando-se um acentuado decréscimo em A e, principalmente, em gs. Nos ramos anelados, os teores de amido aumentaram 271% e 203%, respectivamente, no quarto e no décimo dias após o anelamento, enquanto a razão hexoses:aminoácidos aumentou no décimo dia após a implantação dos tratamentos, em relação aos ramos-controle. Os teores dos demais carboidratos e dos aminoácidos mantiveram-se inalterados. As atividades inicial e total e o estado de ativação da Rubisco, bem como a atividade da AGPase, não foram alteradas com o anelamento. Adicionalmente, a capacidade fotossintética potencial não variou, em resposta ao anelamento, provendo, por conseguinte, forte evidência de que as variações em A foram pouco afetadas por limitações bioquímicas à maquinaria fotossintética. Os decréscimos em A foram explicados principalmente por alterações em gs e não por alterações no metabolismo do carbono, conforme sugere a análise de correlações canônicas. Conclui-se, pois, que as variações nas trocas gasosas ao longo do dia, bem como as variações entre folhas de ramos anelados e não anelados, em café, foram decorrentes meramente de limitações difusivas, e não de possíveis alterações no metabolismo do carbono.Coordenação de Aperfeiçoamento de Pessoal de Nível Superiorapplication/pdfporUniversidade Federal de ViçosaMestrado em Fisiologia VegetalUFVBRControle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superioresCafé arábicaFotossínteseDéficit de pressão de vaporAnelamentoCoffea arabicaCoffeePhotosynthesisVapor pressure deficitGirdlingCoffea arabicaCNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::FISIOLOGIA DE PLANTAS CULTIVADASVariações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábicaDiurnal changes in photosynthesis and effects of branch girdling on photosynthesis and carbon metabolism in arabica coffeeinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccessreponame:LOCUS Repositório Institucional da UFVinstname:Universidade Federal de Viçosa (UFV)instacron:UFVORIGINALtexto completo.pdfapplication/pdf520335https://locus.ufv.br//bitstream/123456789/4292/1/texto%20completo.pdf133b7aafe14e6bfde015c5e172526a0eMD51TEXTtexto completo.pdf.txttexto completo.pdf.txtExtracted texttext/plain71635https://locus.ufv.br//bitstream/123456789/4292/2/texto%20completo.pdf.txt2969093e09be5aa9e55ac07153a9188bMD52THUMBNAILtexto completo.pdf.jpgtexto completo.pdf.jpgIM Thumbnailimage/jpeg3714https://locus.ufv.br//bitstream/123456789/4292/3/texto%20completo.pdf.jpg82251c88403a1d8fbc457a94e529de0eMD53123456789/42922016-04-10 23:06:45.166oai:locus.ufv.br:123456789/4292Repositório InstitucionalPUBhttps://www.locus.ufv.br/oai/requestfabiojreis@ufv.bropendoar:21452016-04-11T02:06:45LOCUS Repositório Institucional da UFV - Universidade Federal de Viçosa (UFV)false |
dc.title.por.fl_str_mv |
Variações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábica |
dc.title.alternative.eng.fl_str_mv |
Diurnal changes in photosynthesis and effects of branch girdling on photosynthesis and carbon metabolism in arabica coffee |
title |
Variações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábica |
spellingShingle |
Variações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábica Batista, Karine Dias Café arábica Fotossíntese Déficit de pressão de vapor Anelamento Coffea arabica Coffee Photosynthesis Vapor pressure deficit Girdling Coffea arabica CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::FISIOLOGIA DE PLANTAS CULTIVADAS |
title_short |
Variações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábica |
title_full |
Variações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábica |
title_fullStr |
Variações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábica |
title_full_unstemmed |
Variações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábica |
title_sort |
Variações diurnas da fotossíntese e efeitos do anelamento de ramos sobre a fotossíntese e o metabolismo do carbono em café arábica |
author |
Batista, Karine Dias |
author_facet |
Batista, Karine Dias |
author_role |
author |
dc.contributor.authorLattes.por.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4774216J5 |
dc.contributor.author.fl_str_mv |
Batista, Karine Dias |
dc.contributor.advisor-co1.fl_str_mv |
Loureiro, Marcelo Ehlers |
dc.contributor.advisor-co1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4780851Y3 |
dc.contributor.advisor-co2.fl_str_mv |
Ventrella, Marília Contin |
dc.contributor.advisor-co2Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4763436A2 |
dc.contributor.advisor1.fl_str_mv |
Damatta, Fábio Murilo |
dc.contributor.advisor1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4784185Y9 |
dc.contributor.referee1.fl_str_mv |
Barros, Raimundo Santos |
dc.contributor.referee1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787859T6 |
dc.contributor.referee2.fl_str_mv |
Ronchi, Cláudio Pagotto |
dc.contributor.referee2Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4767872T7 |
dc.contributor.referee3.fl_str_mv |
Pinheiro, Hugo Alves |
dc.contributor.referee3Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792911A5 |
contributor_str_mv |
Loureiro, Marcelo Ehlers Ventrella, Marília Contin Damatta, Fábio Murilo Barros, Raimundo Santos Ronchi, Cláudio Pagotto Pinheiro, Hugo Alves |
dc.subject.por.fl_str_mv |
Café arábica Fotossíntese Déficit de pressão de vapor Anelamento Coffea arabica |
topic |
Café arábica Fotossíntese Déficit de pressão de vapor Anelamento Coffea arabica Coffee Photosynthesis Vapor pressure deficit Girdling Coffea arabica CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::FISIOLOGIA DE PLANTAS CULTIVADAS |
dc.subject.eng.fl_str_mv |
Coffee Photosynthesis Vapor pressure deficit Girdling Coffea arabica |
dc.subject.cnpq.fl_str_mv |
CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::FISIOLOGIA DE PLANTAS CULTIVADAS |
description |
This study was carried out in order to examine (i) the diurnal changes in photosynthesis rates under low atmospheric evaporative demand, and (ii) the relationship between the rate of net photosynthesis (A) and carbon (C) metabolism in experimentally-manipulated branches through girdling. Two experiments were separately conducted and so analyzed. In both experiments, plants of arabica coffee (Coffea arabica L.) were grown in 12-L pots during approximately eight months. Then, gas exchanges (measured using an infrared gas analyzer), the rate of uptake of 14CO2 and the partitioning of the recently fixed 14C through the major photosynthetic routes were analyzed; leaf material was also harvested for biochemical assays. In Experiment I, plants were grown in a greenhouse under semi-controlled conditions (diurnal values of vapor pressure deficit, VPD, ranging from 1.0 to 1.6 kPa). There was a decrease (20%) in A paralleling a reduction (35%) in stomatal conductance (gs) at 16:00 h as compared with the values of these traits obtained at 08:00 and 12:00 h. The narrow diurnal fluctuations in A were apparently coupled with the maintenance of low VPD throughout the day. Simple and canonical correlations evidenced a lack of feedback inhibition to photosynthesis, a fact further supported by the (i) lack of diurnal changes in carbohydrate and amino acid levels and (ii) unchanging rate of 14CO2 uptake and the partitioning of the recently fixed 14C during the day. In addition, the activity of ADP-glucose pyrophosphorylase and the initial and total activities of Rubisco (as well as its activation state) did not change during the day. In fact, diurnal variations in A were largely explained by diffusive limitations. In Experiment II, gas exchange was measured at 08:00 h during 11 days in girdled and non-girdled (control) branches. There was a remarkable decrease in A and especially in gs. In girdled branches, starch levels increased by 271% and 203%, respectively at the 4th and 10th days after applying the treatments. The hexose-to-amino acid ratio increased in girdled branches at the 10th day of girdling, but the concentrations of other soluble sugars and amino acids did no change in response to the treatments, as also did the activity of ADP-glucose pyrophosphorylase and the initial and total activities of Rubisco. Moreover, the potential photosynthetic capacity also remained unchanged after girdling, suggesting that changes in A were marginally affected, if so, by biochemical constraints to the photosynthetic machinery. As in Experiment I, changes in A were largely explained by diffusive limitations. In summary, it is proposed that diurnal oscillations in A during the day, as well as between leaves from girdled and non-girdled branches were merely a consequence from diffusive, rather than from biochemical, limitations to photosynthesis. |
publishDate |
2008 |
dc.date.available.fl_str_mv |
2008-09-08 2015-03-26T13:36:36Z |
dc.date.issued.fl_str_mv |
2008-02-26 |
dc.date.accessioned.fl_str_mv |
2015-03-26T13:36:36Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
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masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
BATISTA, Karine Dias. Diurnal changes in photosynthesis and effects of branch girdling on photosynthesis and carbon metabolism in arabica coffee. 2008. 43 f. Dissertação (Mestrado em Controle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superiores) - Universidade Federal de Viçosa, Viçosa, 2008. |
dc.identifier.uri.fl_str_mv |
http://locus.ufv.br/handle/123456789/4292 |
identifier_str_mv |
BATISTA, Karine Dias. Diurnal changes in photosynthesis and effects of branch girdling on photosynthesis and carbon metabolism in arabica coffee. 2008. 43 f. Dissertação (Mestrado em Controle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superiores) - Universidade Federal de Viçosa, Viçosa, 2008. |
url |
http://locus.ufv.br/handle/123456789/4292 |
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por |
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Universidade Federal de Viçosa |
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Mestrado em Fisiologia Vegetal |
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UFV |
dc.publisher.country.fl_str_mv |
BR |
dc.publisher.department.fl_str_mv |
Controle da maturação e senescência em órgãos perecíveis; Fisiologia molecular de plantas superiores |
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Universidade Federal de Viçosa |
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