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Registros recuperados: 220 | |
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Jiang,Zhongyang; Peiyong,Guo; Chang,Cheinchi; Gao,Lili; Li,Shixiong; Wan,Jinjin. |
This study was performed in order to isolate and identify unknown allelochemicals from Ficus microcarpa, and to investigate the inhibitory to bloom-forming of green alga Chlorella pyrenoidosa. Through gradient elution, fraction C2, whose inhibition of alga growth in diverse extracts was the strongest was shown to cause significant reductions of maximum quantum yield, as well as electron transport rates of C. pyrenoidosa. The study data also showed that the increase of fraction C2 concentration decreased the activity of total superoxide dismutase (SOD), but increased the activities of catalase (CAT) and malondialdehyde (MDA) content. These results demonstrate that the active fraction C2 not only induced the photoinhibition or photodamage of PSII reaction... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Allelochemical; Phenols; Photosynthesis; Ficus microcarpa; Chlorella pyrenoidosa. |
Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132014000400595 |
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Harris-Valle,Citlalli; Esqueda,Martín; Gutiérrez,Aldo; Castellanos,Alejandro E.; Gardea,Alfonso A.; Berbara,Ricardo. |
ABSTRACT Plants response to symbiosis with arbuscular mycorrhizal fungi (AMF) under water stress is important to agriculture. Under abiotic stress conditions native fungi are more effective than exotics in improving plant growth and water status. Mycorrhization efficiency is related to soil fungi development and energy cost-benefit ratio. In this study, we assessed the effect on growth, water status and energy metabolism of Cucurbita pepo var. pepo when inoculated with native AMF from the Sonoran desert Mexico (mixed isolate and field consortium), and compared with an exotic species from a temperate region, under drought, low and high salinity conditions. Dry weights, leaf water content, water and osmotic potentials, construction costs, photochemistry and... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glomus; Pacispora; Water status; Construction cost; Photosynthesis. |
Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822018000100045 |
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Dalmolin,Ândrea Carla; Dalmagro,Higo José; Lobo,Francisco de Almeida; Antunes Junior,Mario Zortéa; Ortíz,Carmen Eugenia Rogríguez; Vourlitis,George Louis. |
Vochysia divergens Pohl (commonly known as cambara) is a pioneer tree species that is native to the Amazon Basin but has been invading the seasonally flooded wetlands of the Brazilian Pantanal, forming monospecific communities. The physiological aspects associated with cambara invasion, including the effects of flooding and shading on growth and leaf gas exchange, are unknown but may shed light on why cambara is able to invade this novel habitat so rapidly. Thus, we conducted a manipulative experiment to quantify the effects of shading and flooding on the growth, gas exchange and leaf nutrient content of V. divergens saplings. Based on previous research we hypothesized that (1) experimental flooding would have no effect on the growth and gas exchange of V.... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cambara; Physiological stress; Photosynthesis; Plant ecophysiology; Stomatal conductance; Tropical wetlands. |
Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202012000200001 |
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Marchese,José Abramo; Broetto,Fernando; Ming,Lin Chau; Ducatti,Carlos; Rodella,Roberto Antonio; Ventrella,Marília Contin; Gomes,Greice Daiane Rodrigues; Franceschi,Lúcia de. |
Leaves of Artemisia annua L. are a plentiful source of artemisinin, a drug with proven effectiveness against malaria. The aim of this study was to classify the photosynthetic mechanism of A. annua through studies of the carbon isotope composition (delta 13C) and the leaf anatomy. A. annua presented a delta 13C value of - 31.76 ± 0.07, which characterizes the plants as a typical species of the C3 photosynthethic mechanism, considering that the average delta 13C values for C3 and C4 species are -28 and -14, respectively. The leaf anatomy studies were consistent with the delta 13C results, where, in spite of the existence of parenchymatic cells forming a sheath surrounding the vascular tissue, the cells do not contain chloroplasts or starch. This... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: C3 and C4 plants; Isotope discrimination; Kranz anatomy; Photosynthesis. |
Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000100016 |
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Habermann,Gustavo; Machado,Silvia R.; Guimarães,Vandeir F.; Rodrigues,João D.. |
Styrax camporum is a common shrub species from the cerrado regions of São Paulo State, Brazil. Although its leaves do not have a morphologically delimited pulvinus, the apical leaves are oriented parallel to the sun (paraheliotropic leaves), most notably around noon. Horizontal leaves at the base of shoots are oriented perpendicular to the sun's rays (diaheliotropic leaves). The ecophysiological significance of this is not fully understood. We investigated how paraheliotropism influences daily CO2 assimilation (A) and other gas exchange rates, water relations, leaf temperature (Tl), and how these relate to leaf structure as assessed by anatomical leaf descriptions. Paraheliotropic leaves had greater A and stomatal conductance (g s), which led to greater... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brazilian savanna; Ecophysiology; Gas exchange; Leaf movements; Leaf temperature; Photosynthesis; Styracaceae. |
Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202008000100008 |
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DaMatta,Fábio M.. |
In this special issue, ecophysiology of major tropical tree crops, considered here on a broader sense and including species such as banana, cashew, cassava, citrus, cocoa, coconut, coffee, mango, papaya, rubber, and tea, are examined. For most of these crops, photosynthesis is treated as a central process affecting growth and crop performance. The crop physiological responses to environmental factors such as water availability and temperature are highlighted. Several gaps in our database concerning ecophysiology of tropical tree crops are indicated, major advances are examined, and needs of further researches are delineated. |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Crop growth and production; Environmental stresses and physiology; Photosynthesis; Gas exchange; Tropical tree crops. |
Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202007000400001 |
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Costa,Ernany Santos; Bressan-Smith,Ricardo; Oliveira,Jurandi Gonçalves de; Campostrini,Eliemar; Pimentel,Carlos. |
Bean (Phaseolus vulgaris L., cv. Carioca and cv. Negro Huasteco) and cowpea plants (Vigna unguiculata L. Walp cv. Epace 10) were grown in a growth chamber with PPF at leaf level of 200 mumol.m-2.s-1 and air temperature 25 + 1 ºC. The first fully expanded pair of leaves of 12-day-old plants was submitted to high temperature stress (25, 30, 35, 40, 45 and 48 ºC) for 1.5 h. The photochemical efficiency of PSII during recovery was monitored by means of chlorophyll a fluorescence at six different times (0.5, 1, 2, 4, 24, and 48 h) after stress, at 25 ºC, using a modulated fluorimeter. Increasing temperature promoted an increase in Fphi at 45 ºC, possibly associated with dissociation of the light harvesting complex from the reaction centre of PSII, but a... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chlorophyll a fluorescence; Heat stress; Photosynthesis. |
Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202002000200004 |
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Vieira Jr.,Jair; Necchi Jr.,Orlando. |
Photosynthetic characteristics (assessed by chlorophyll fluorescence and O2 evolution) were analysed monthly during one year in a tropical population of Nitella cernua from southeastern Brazil (20º50'32" S, 49º26'15" W). Parameters derived from photosynthesis-irradiance (PI) curves by fluorescence (high values of the photosynthetic parameter, Ik, and lack or low values of photoinhibition, beta) suggested adaptation to high irradiance, whereas those by O2 evolution showed a different pattern (low values of Ik and compensation irradiance, Ic, high values of photosynthetic efficiency, alpha, and photoinhibition). Parameters from PI curves by O2 evolution suggested light acclimation: Ik and maximum photosynthetic rate, Pmax (as rETR, relative electron transfer... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Charophytes; Irradiance; Nitella; PH; Photosynthesis; Seasonal dynamics; Temperature. |
Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202006000300004 |
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Aragão,Maria Erivalda Farias de; Guedes,Marjorie Moreira; Otoch,Maria de Lourdes Oliveira; Guedes,Maria Izabel Florindo; Melo,Dirce Fernandes de; Lima,Maria da Guia Silva. |
Vita 3 and Vita 5 are two Vigna unguiculata cultivars that differ in their capacities for survival in saline environments; Vita 3 is more tolerant and Vita 5 more sensitive. Both cultivars were submitted to salt stress with 0.1 M NaCl. After 8 days, root and shoot growth from both cultivars was reduced but reduction was more pronounced in Vita 5. Furthermore, leaf area was also reduced in this cultivar. Chlorophyll content and chlorophyll fluorescence parameters were not affected by salt stress, but the specific activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) decreased in Vita 3 and increased in Vita 5. The use of immunological techniques also revealed that the Rubisco content from Vita 3 decreased while that of Vita 5 increased.... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Rubisco; Photosynthesis; Salt stress; Vigna unguiculata. |
Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000200003 |
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Santos,Mauro Guida dos; Ribeiro,Rafael Vasconcelos; Oliveira,Ricardo Ferraz de; Pimentel,Carlos. |
This study was conducted to evaluate the effect of foliar Pi application on gas exchange and yield of bean genotypes submitted to a mild water deficit at the pre-flowering stage. In the first experiment, when extra Pi (10 g.L-1) was sprayed on leaves during water stress or during recovery, there was no effect on gas exchange or yield in the A320, Carioca and Ouro Negro genotypes. However, net CO2 assimilation (A) of A320 and Ouro Negro was less affected, but not significantly, than Carioca at the end of the stress, when Pi was supplied five days before water deficit. In the second experiment, two different doses of Pi (10 and 20 g.Pi L-1) were sprayed five days before water deficit on the Carioca genotype. During the last three days of the mild water... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Common bean; Inorganic phosphorus; Photosynthesis; Water deficit. |
Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202004000300007 |
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Souza,Gustavo M.; Pincus,Steven M; Monteiro,José Alberto F.. |
We hypothesized that more complex, i.e. irregular, temporal dynamics and a more interconnected overall network supports greater stability to gas exchange parameters (herein, CO2 net assimilation and transpiration) in plants under water deficit. To test this hypothesis two genotypes of Phaseolus vulgaris were subjected to a period of absence of irrigation, and subsequent rewatering to achieve recovery. Gas exchanges parameters were measured each 10 s during 6 h to obtain time series to evaluate complexity by Approximate Entropy (ApEn) calculations, and network connectance in each water regime. Notably, the Jalo Precoce genotype showed significantly more stability than the Guarumbé genotype under system perturbation, coincident with greater irregularity in... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Approximate Entropy; Complexity; Network connectance; Plant stress theory; Photosynthesis; Temporal dynamics; Water deficit. |
Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000400004 |
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Coscolin,Renata B. S.; Broetto,Fernando; Marchese,José A.; Campohermoso,Marco C.; Paladini,Marcos V.. |
The metabolic effects caused by hydric deficiency (HD) on Eucalyptus grandis clones were assessed by an experiment where plants were cultivated in four blocks. The first was the control block, normally irrigated, whereas the other three blocks were submitted to cycles of hydric deficiency. Analysis of photosynthetic efficiency, enzymatic activity of antioxidant response system, level of pigments and L-proline concentration were performed to evaluate the HD effects. Results showed that HD altered some parameters related to photosynthetic activity, pigments accumulation, proline and enzymatic activity. Clone 433 of E. grandis presented higher response ability to HD. |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Enzymes; Eucalypt; Hydric deficiency; Photosynthesis. |
Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202011000400002 |
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Registros recuperados: 220 | |
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