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  1 / 8 MEDLINE  
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[PMID]:27553681
[Au] Autor:Ambrose AR; Baxter WL; Wong CS; Burgess SS; Williams CB; Næsborg RR; Koch GW; Dawson TE
[Ad] Endereço:Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA. ambrose@berkeley.edu.
[Ti] Título:Hydraulic constraints modify optimal photosynthetic profiles in giant sequoia trees.
[So] Source:Oecologia;182(3):713-30, 2016 Nov.
[Is] ISSN:1432-1939
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Optimality theory states that whole-tree carbon gain is maximized when leaf N and photosynthetic capacity profiles are distributed along vertical light gradients such that the marginal gain of nitrogen investment is identical among leaves. However, observed photosynthetic N gradients in trees do not follow this prediction, and the causes for this apparent discrepancy remain uncertain. Our objective was to evaluate how hydraulic limitations potentially modify crown-level optimization in Sequoiadendron giganteum (giant sequoia) trees up to 90 m tall. Leaf water potential (Ψ l ) and branch sap flow closely followed diurnal patterns of solar radiation throughout each tree crown. Minimum leaf water potential correlated negatively with height above ground, while leaf mass per area (LMA), shoot mass per area (SMA), leaf nitrogen content (%N), and bulk leaf stable carbon isotope ratios (δ(13)C) correlated positively with height. We found no significant vertical trends in maximum leaf photosynthesis (A), stomatal conductance (g s), and intrinsic water-use efficiency (A/g s), nor in branch-averaged transpiration (E L), stomatal conductance (G S), and hydraulic conductance (K L). Adjustments in hydraulic architecture appear to partially compensate for increasing hydraulic limitations with height in giant sequoia, allowing them to sustain global maximum summer water use rates exceeding 2000 kg day(-1). However, we found that leaf N and photosynthetic capacity do not follow the vertical light gradient, supporting the hypothesis that increasing limitations on water transport capacity with height modify photosynthetic optimization in tall trees.
[Mh] Termos MeSH primário: Sequoiadendron
Árvores
[Mh] Termos MeSH secundário: Fotossíntese
Folhas de Planta
Transpiração Vegetal
Água
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
059QF0KO0R (Water)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:171010
[Lr] Data última revisão:
171010
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160825
[St] Status:MEDLINE
[do] DOI:10.1007/s00442-016-3705-3


  2 / 8 MEDLINE  
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[PMID]:27208348
[Au] Autor:Chin AR; Sillett SC
[Ad] Endereço:Department of Natural Resources, American River College, 4700 College Oak Drive, Sacramento, California 95841 USA alanaroseo@gmail.com.
[Ti] Título:Phenotypic plasticity of leaves enhances water-stress tolerance and promotes hydraulic conductivity in a tall conifer.
[So] Source:Am J Bot;103(5):796-807, 2016 05.
[Is] ISSN:1537-2197
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PREMISE OF THE STUDY: Leaves respond to environmental signals and acclimate to local conditions until their ecological limits are reached. Understanding the relationships between anatomical variation in leaves and the availability of water and light improves our ability to predict ecosystem-level impacts of foliar response to climate change, as it expands our knowledge of tree physiology. METHODS: We examined foliar anatomy and morphology of the largest plant species, Sequoiadendron giganteum, from leafy shoot samples collected throughout crowns of trees up to 95 m tall and assessed the functionality of within-crown variation with a novel drought/recovery experiment. KEY RESULTS: We found phenotypic variation in response to water availability in 13 anatomical traits of Sequoiadendron leaves. Shoot expansion was constrained by the hydrostatic gradient of maximum water potential, while functional traits supporting succulence and toughness were associated with sites of peak hydraulic limitation. Water-stress tolerance in experimental shoots increased dramatically with height. CONCLUSION: We propose a heat-sink function for transfusion tissue and uncover a suite of traits suggesting rapid hydraulic throughput and flexibility in water-stress tolerance investments as strategies that help this montane species reach such enormous size. Responses to water stress alter the amount of carbon stored in foliage and the rate of the eventual release of carbon.
[Mh] Termos MeSH primário: Adaptação Fisiológica
Coniferophyta/fisiologia
Folhas de Planta/fisiologia
Estresse Fisiológico
Água/fisiologia
[Mh] Termos MeSH secundário: Coniferophyta/anatomia & histologia
Secas
Fenótipo
Brotos de Planta/anatomia & histologia
Brotos de Planta/fisiologia
Sequoiadendron/fisiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
059QF0KO0R (Water)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:171121
[Lr] Data última revisão:
171121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160522
[St] Status:MEDLINE
[do] DOI:10.3732/ajb.1600110


  3 / 8 MEDLINE  
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[PMID]:26041093
[Au] Autor:Brodribb TJ; McAdam SA
[Ad] Endereço:Department of Plant Science, University of Tasmania, Hobart, Tasmania, Australia timothyb@utas.edu.au.
[Ti] Título:Evolution in the smallest valves (stomata) guides even the biggest trees.
[So] Source:Tree Physiol;35(5):451-2, 2015 May.
[Is] ISSN:1758-4469
[Cp] País de publicação:Canada
[La] Idioma:eng
[Mh] Termos MeSH primário: Secas
Sequoia/fisiologia
Sequoiadendron/fisiologia
Estresse Fisiológico
[Pt] Tipo de publicação:COMMENT; JOURNAL ARTICLE
[Em] Mês de entrada:1603
[Cu] Atualização por classe:150604
[Lr] Data última revisão:
150604
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150605
[St] Status:MEDLINE
[do] DOI:10.1093/treephys/tpv042


  4 / 8 MEDLINE  
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[PMID]:25787330
[Au] Autor:Ambrose AR; Baxter WL; Wong CS; Næsborg RR; Williams CB; Dawson TE
[Ad] Endereço:Department of Integrative Biology, University of California, Berkeley, CA 94720, USA ambrose@berkeley.edu.
[Ti] Título:Contrasting drought-response strategies in California redwoods.
[So] Source:Tree Physiol;35(5):453-69, 2015 May.
[Is] ISSN:1758-4469
[Cp] País de publicação:Canada
[La] Idioma:eng
[Ab] Resumo:We compared the physiology and growth of seedlings originating from different Sequoia sempervirens (D. Don.) Endl. (coast redwood) and Sequoiadendron giganteum (Lindl.) Buchh. (giant sequoia) populations subjected to progressive drought followed by a recovery period in a controlled greenhouse experiment. Our objective was to examine how multiple plant traits interact to influence the response of seedlings of each species and seed population to a single drought and recovery cycle. We measured soil and plant water status, leaf gas exchange, stem embolism and growth of control (well-watered) and drought-stressed (water withheld) seedlings from each population at the beginning, middle and end of a 6-week drought period and again 2 weeks after re-watering. The drought had a significant effect on many aspects of seedling performance, but water-stressed seedlings regained most physiological functioning by the end of the recovery period. Sequoiadendron seedlings exhibited a greater degree of isohydry (water status regulation), lower levels of stem embolism, higher biomass allocation to roots and lower sensitivity of growth to drought compared with Sequoia. Only minor intra-specific differences were observed among populations. Our results show that seedlings of the two redwood species exhibit contrasting drought-response strategies that align with the environmental conditions these trees experience in their native habitats, and demonstrate trade-offs and coordination among traits affecting plant water use, carbon gain and growth under drought.
[Mh] Termos MeSH primário: Secas
Sequoia/fisiologia
Sequoiadendron/fisiologia
Estresse Fisiológico
[Mh] Termos MeSH secundário: California
Clima
Plântulas/genética
Plântulas/crescimento & desenvolvimento
Plântulas/fisiologia
Sequoia/genética
Sequoia/crescimento & desenvolvimento
Sequoiadendron/genética
Sequoiadendron/crescimento & desenvolvimento
Especificidade da Espécie
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1603
[Cu] Atualização por classe:150604
[Lr] Data última revisão:
150604
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150320
[St] Status:MEDLINE
[do] DOI:10.1093/treephys/tpv016


  5 / 8 MEDLINE  
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[PMID]:22844856
[Au] Autor:Nijhuis M
[Ti] Título:Which species will live?
[So] Source:Sci Am;307(2):74-9, 2012 Aug.
[Is] ISSN:0036-8733
[Cp] País de publicação:United States
[La] Idioma:eng
[Mh] Termos MeSH primário: Conservação dos Recursos Naturais/métodos
Espécies em Perigo de Extinção
[Mh] Termos MeSH secundário: Animais
Aves
Golfinhos
Ecologia
Ecossistema
Variação Genética
Rhizophoraceae
Sequoiadendron
Lobos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1209
[Cu] Atualização por classe:120731
[Lr] Data última revisão:
120731
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:120801
[St] Status:MEDLINE


  6 / 8 MEDLINE  
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[PMID]:22492401
[Au] Autor:Fahey C; York RA; Pawlowska TE
[Ad] Endereço:Department of Plant Pathology & Plant Microbe-Biology, Cornell University, Ithaca, NY 14853, USA.
[Ti] Título:Arbuscular mycorrhizal colonization of giant sequoia (Sequoiadendron giganteum) in response to restoration practices.
[So] Source:Mycologia;104(5):988-97, 2012 Sep-Oct.
[Is] ISSN:0027-5514
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Interactions with soil microbiota determine the success of restoring plants to their native habitats. The goal of our study was to understand the effects of restoration practices on interactions of giant sequoia Sequoiadendron giganteum with arbuscular mycorrhizal (AM) fungi (Glomeromycota). Natural regeneration of Sequoiadendron is threatened by the absence of severe fires that create forest canopy gaps. Generating artificial canopy gaps offers an alternative tool for giant sequoia restoration. We investigated the effect of regeneration practices, including (i) sapling location within gaps, (ii) gap size and (iii) soil substrate, on AM fungal colonization of giant sequoia sapling roots in a native giant sequoia grove of the Sierra Nevada, California. We found that the extent of AM fungal root colonization was positively correlated with sapling height and light availability, which were related to the location of the sapling within the gap and the gap size. While colonization frequency by arbuscules in saplings on ash substrate was higher relative to saplings in mineral soil, the total AM fungal root colonization was similar between the substrates. A negative correlation between root colonization by Glomeromycota and non-AM fungal species indicated antagonistic interactions between different classes of root-associated fungi. Using DNA genotyping, we identified six AM fungal taxa representing genera Glomus and Ambispora present in Sequoiadendron roots. Overall, we found that AM fungal colonization of giant sequoia roots was associated with availability of plant-assimilated carbon to the fungus rather than with the AM fungal supply of mineral nutrients to the roots. We conclude that restoration practices affecting light availability and carbon assimilation alter feedbacks between sapling growth and activity of AM fungi in the roots.
[Mh] Termos MeSH primário: Glomeromycota/fisiologia
Micorrizas/crescimento & desenvolvimento
Sequoiadendron/crescimento & desenvolvimento
Sequoiadendron/microbiologia
[Mh] Termos MeSH secundário: California
Carbono/metabolismo
Ecossistema
Glomeromycota/genética
Glomeromycota/crescimento & desenvolvimento
Glomeromycota/metabolismo
Minerais/metabolismo
Micorrizas/efeitos dos fármacos
Micorrizas/metabolismo
Sequoiadendron/metabolismo
Solo
Árvores
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Minerals); 0 (Soil); 7440-44-0 (Carbon)
[Em] Mês de entrada:1211
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:120412
[St] Status:MEDLINE
[do] DOI:10.3852/11-289


  7 / 8 MEDLINE  
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[PMID]:20435080
[Au] Autor:Bajpai VK; Na M; Kang SC
[Ad] Endereço:Department of Biotechnology, Daegu University, Kyoungsan, Kyoungbook 712-714, Republic of Korea.
[Ti] Título:The role of bioactive substances in controlling foodborne pathogens derived from Metasequoia glyptostroboides Miki ex Hu.
[So] Source:Food Chem Toxicol;48(7):1945-9, 2010 Jul.
[Is] ISSN:1873-6351
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:In an attempt to isolate bioactive substances, ethyl acetate cone extract of Metasequoia glyptostroboides was subjected to a column chromatographic analysis that resulted in isolation of an abietane type diterpenoid, taxoquinone. Its structure was elucidated by spectroscopic means. In further, taxoquinone showed potential antibacterial effect as diameters of zones of inhibition against foodborne pathogenic bacteria such as Listeria monocytogenes ATCC 19166, Salmonella typhimurium KCTC 2515, Salmonella enteritidis KCTC 2021, Escherichia coli ATCC 8739, E. coli O157:H7 ATCC 43888, Enterobacter aerogenes KCTC2190, Staphylococcus aureus ATCC 6538 and S. aureus KCTC 1916, which were found in the range of 10.6-15.8mm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of taxoquinone against the employed bacterial pathogens were found in the range of 62.5-250 and 125-500 microg/ml. Also the compound had strong antibacterial effect on the viable counts of the tested bacteria. Further, scanning electron microscopic study demonstrated potential detrimental effect of taxoquinone on the morphology of E. coli ATCC 8739. These findings indicate that bioactive compound taxoquinone present in M. glyptostroboides could be used as a promising antibacterial agent in food industry to inhibit the growth of certain important foodborne pathogens.
[Mh] Termos MeSH primário: Antibacterianos/farmacologia
Contaminação de Alimentos/análise
Microbiologia de Alimentos
Sequoiadendron/química
[Mh] Termos MeSH secundário: Bactérias/efeitos dos fármacos
Carga Bacteriana
Escherichia coli/efeitos dos fármacos
Escherichia coli/ultraestrutura
Testes de Sensibilidade Microbiana
Microscopia Eletrônica de Varredura
Extratos Vegetais/farmacologia
Quinonas/farmacologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Anti-Bacterial Agents); 0 (Plant Extracts); 0 (Quinones)
[Em] Mês de entrada:1011
[Cu] Atualização por classe:100804
[Lr] Data última revisão:
100804
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:100504
[St] Status:MEDLINE
[do] DOI:10.1016/j.fct.2010.04.041


  8 / 8 MEDLINE  
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[PMID]:19210642
[Au] Autor:Ambrose AR; Sillett SC; Dawson TE
[Ad] Endereço:Department of Integrative Biology, University of California, Berkeley, CA 94720, USA. ambrose@berkeley.edu
[Ti] Título:Effects of tree height on branch hydraulics, leaf structure and gas exchange in California redwoods.
[So] Source:Plant Cell Environ;32(7):743-57, 2009 Jul.
[Is] ISSN:1365-3040
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We examined changes in branch hydraulic, leaf structure and gas exchange properties in coast redwood (Sequoia sempervirens) and giant sequoia (Sequoiadendron giganteum) trees of different sizes. Leaf-specific hydraulic conductivity (k(L)) increased with height in S. sempervirens but not in S. giganteum, while xylem cavitation resistance increased with height in both species. Despite hydraulic adjustments, leaf mass per unit area (LMA) and leaf carbon isotope ratios (delta(13)C) increased, and maximum mass-based stomatal conductance (g(mass)) and photosynthesis (A(mass)) decreased with height in both species. As a result, both A(mass) and g(mass) were negatively correlated with branch hydraulic properties in S. sempervirens and uncorrelated in S. giganteum. In addition, A(mass) and g(mass) were negatively correlated with LMA in both species, which we attributed to the effects of decreasing leaf internal CO(2) conductance (g(i)). Species-level differences in wood density, LMA and area-based gas exchange capacity constrained other structural and physiological properties, with S. sempervirens exhibiting increased branch water transport efficiency and S. giganteum exhibiting increased leaf-level water-use efficiency with increasing height. Our results reveal different adaptive strategies for the two redwoods that help them compensate for constraints associated with growing taller, and reflect contrasting environmental conditions each species faces in its native habitat.
[Mh] Termos MeSH primário: Folhas de Planta/fisiologia
Caules de Planta/fisiologia
Transpiração Vegetal/fisiologia
Sequoia/fisiologia
Sequoiadendron/fisiologia
[Mh] Termos MeSH secundário: Isótopos de Carbono
Fotossíntese/fisiologia
Árvores/fisiologia
Água/fisiologia
Xilema/fisiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Carbon Isotopes); 059QF0KO0R (Water)
[Em] Mês de entrada:0908
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:090213
[St] Status:MEDLINE
[do] DOI:10.1111/j.1365-3040.2009.01950.x



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