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| Registros recuperados: 46 | |
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| CASANOVA-KATNY,M. ANGÉLICA; BRAVO,LEÓN A; MOLINA-MONTENEGRO,MARCO; CORCUERA,LUIS J; CAVIERES,LOHENGRIN A. |
| Photosynthesis of Colobanthus quitensis and mesoclimatic conditions of air temperature and light intensity during the growing season were investigated at 2,650 m in the central Chilean Andes. On three typical days of the growing period (January, March and May), CO2 exchange and chlorophyll fluorescence were measured. In addition, a series of fluorescence response curves with increasing light intensity at different temperatures were performed to estimate the propensity of Andean C. quitensis populations to be photoinhibited. Net Photosynthesis (Pn) was low (ca. 2.0 mmol CO2 m-2s-1) during the morning and noon in days with high photosynthetic active radiation (PAR, above 1,800 mmol photons m-2s-1). Pn increased in the afternoon (3.5-4.8 mmol CO2 m-2s-1) when... |
| Tipo: Journal article |
Palavras-chave: Net photosynthesis; Chlorophyll fluorescence; NPQ; Alpine climate; Alpine plants; Andes. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2006000100004 |
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| Silva,Evandro Nascimento da; Ribeiro,Rafael Vasconcelos; Ferreira-Silva,Sérgio Luiz; Viégas,Ricardo Almeida; Silveira,Joaquim Albenisio Gomes. |
| Salinity is a major limiting factor to crop productivity in the world especially in semiarid regions. The aim of this study was to evaluate the photosynthetic resistance of Jatropha curcas (L.) young plants subjected to salt stress. The experiment was carried out in a completely randomized design with treatments in a 2 x 3 factorial: two NaCl levels (0 and 100 mmol L-1) and three harvest times: 7 and 14 days of salt exposure and three days of recovery. Leaf Na+ and Cl-concentrations and the K+/Na+ ratios, after seven days of salt exposure, did not reach ionic toxic levels, suggesting that the NaCl-induced osmotic effects prevailed over the ionic ones. Under this condition, the salt stress caused reduction in leaf gas exchange parameters, such as CO2... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Jatropha curcas; Chlorophyll fluorescence; Gas exchange; Ionic toxicity; Salinity. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162011000100010 |
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| Jaimez,Ramón; Loor,Rey; Arteaga,Francisco; Márquez,Víctor; Tezara,Wilmer. |
| Abstract Cacao (Theobroma cacao L.) is not frequently cropped in water limited environments, however it is cultivated in several drought-prone regions, where soil water is gradually depleted on an annual cycle. In regions where cacao is subjected to long periods without precipitation, the physiological responses under field conditions may differ between cacao clones. Evaluation of these responses are required to select potential clones that could be used for breeding programs in the context of future climatic scenarios. In order to identify physiological and yield responses to drought of 10 Ecuadorian cacao clones, relative leaf water content (RWC), CO2 assimilation rate (A), transpiration (E), stomatal conductance (gs), water use efficiency (WUE),... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cacao; Chlorophyll fluorescence; Photochemical protection; Photosynthesis; Water deficit. |
| Ano: 2021 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-28122021000300274 |
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| PEREZ MARTINEZ,Laura Victoria; MELGAREJO,Luz Marina. |
| Gulupa, Passiflora edulis Sims (Passifloraceae), is an important fruit due to its organoleptic and nutritional characteristics and its demand in the international market; however, very few studies have been conducted for studying its Ecophysiology. Until now, this crop has spread throughout the country through empirical knowledge without data that indicate the zones that are more suitable for its cultivation. For this reason, gas exchange, chlorophyll fluorescence (photosystem II operating efficiency and maximum quantum efficiency of photosystem II photochemistry) and leaf water potential were measured in three different locations of Cundinamarca department (Chia [2610 m a.s.l., 14 °C], Granada [2230 m a.s.l., 15 °C] and Tena [2090 m a.s.l., 17 °C]), whose... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chlorophyll fluorescence; Crop; Horticulture; Passion fruit; Photosynthesis; Plant physiology; Water. |
| Ano: 2015 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2015000100019 |
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| JAIMEZ,Ramon Eduardo; AMORES PUYUTAXI,Freddy; VASCO,Alfonso; Gastón LOOR,Rey; TARQUI,Omar; QUIJANO,Grisnel; JIMENEZ,Juan Carlos; TEZARA,Wilmer. |
| ABSTRACT Cacao (Theobroma cacao L.) breeding programmes in Ecuador have focused on obtaining high-yield clones with improved disease resistance. Cacao clones should also have photosynthetic characteristics which support increased productivity. Regarding the weather conditions at the coast of Ecuador, where most of the year there are overcasts and low air evaporative demand, there is the possibility to grow cacao without overhead shade. This study focused on the photosynthetic response at two different photosynthetic photon flux densities (PPFD) of Ecuadorian cacao clones. Seven-year old cacao clones were evaluated: eight clones of Nacional type and two commercial clones (CCN 51 and EET 103), used as controls. All clones showed an increase of 35 % on... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cacao yield; Chlorophyll fluorescence; CO2 assimilation rate; Gas exchange. |
| Ano: 2018 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2018000100095 |
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| Frosi,Gabriella; Harand,Wolfgang; Oliveira,Marciel Teixeira de; Pereira,Silvia; Cabral,Simone Pereira; Montenegro,Abelardo Antônio de Assunção; Santos,Mauro Guida. |
| ABSTRACT The effects of water deficit on physiological and biochemical variables of young plants of two tropical woody species, Pachira aquatica and Sterculia foetida, and their recovery abilities were measured. Leaf water potential, gas exchange and selected carbon metabolism components were measured in a greenhouse experiment with control, moderate and severe water deficit treatments. Under severe drought stress, gas exchange and chlorophyll fluorescence decreased in both species compared to their respective controls. After rehydration, P. aquatica and S. foetida showed a partial and full recovery of the measured variables, respectively. In addition, a decrease and an increase in photosynthetic pigments were observed for P. aquatica and S. foetida,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chlorophyll fluorescence; Climate changes; Gas exchange; Semiarid; Water deficit. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062017000200153 |
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| Hampp,Rüdiger; Cardoso,Nelsa; Fleig,Mariana; Grüninger,Werner. |
| ABSTRACT The vitality of 64 lichen species (107 individual lichen thalli) growing under different light climates in an Araucaria forest in South Brazil was analyzed by chlorophyll fluorescence. Study sites were grouped according to their local light availability under full sunlight (about 2200 µmol m-2 s-1): 1 = low light, up to 20 µmol m-2 s-1; 2 = medium light, 20 to 100 µmol m-2 s-1; and 3 = high light, more than 100 µmol m-2 s-1. Maximum quantum yield of photosystem II, as shown by Fv/Fm of dark-adapted samples, was mainly between 0.3 and 0.7, with extremes of below 0.1 and up to 0.85. On average, yields were highest with low light availability (0.66). Groups 1 and 2 were not significantly different from each other, but groups 1 and 3, as well as... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Araucaria forest; Chlorophyll fluorescence; Heat dissipation; Lichens; PAM fluorometer; Photosynthetic yield. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062018000200188 |
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| Ribeiro,Rafael Vasconcelos; Santos,Mauro Guida dos; Pimentel,Carlos; Machado,Eduardo Caruso; Oliveira,Ricardo Ferraz de. |
| Low water availability and high temperatures occur under field conditions and we hypothesize that the critical temperature for photochemical damage (TC) in common bean (Phaseolus vulgaris L.) plants is increased by the occurrence of previous water deficit in a genotype-dependent manner. Five common bean cultivars A320, A222, Carioca, BAT477 and Ouro Negro were evaluated. Thirty days after seedlings emergence, one group of plants was exposed to water deficit for ten days and rehydrated and another one was maintained well hydrated during the experimental period. The minimum chlorophyll fluorescence (FO) was monitored in leaf discs exposed to temperatures ranging from 25 to 45 oC and the TC values estimated. The previous water deficit did not affect TC, which... |
| Tipo: Info:eu-repo/semantics/report |
Palavras-chave: Chlorophyll fluorescence; Hardening; Heat stress; Phaseolus vulgaris; Tolerance. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000400374 |
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| Mengarda,Liana H. G.; Souza,Rogério L. F. de; Campostrini,Eliemar; Reis,Fabrício O.; Vendrame,Wagner A.; Cuzzuol,Geraldo R. F.. |
| The ecophysiological behavior of brazilwood (Caesalpinia echinata Lam.) plants was evaluated as affected by light quantity and quality. Nine-month-old plants were cultivated under 0%, 50%, and 80% artificial shading, and natural shading imposed by a closed canopy for a period of 392 days. At the end of that period growth parameters were measured, including relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), specific leaf mass (SLM) and root:shoot ratio (R:S). Higher leaf area, dry mass and RGR were obtained under 50% artificial shade. Under full sunlight (0% shade), growth was satisfactory showing higher R:S and SLM. Growth was inhibited under 80% artificial and natural shading indicating that C. echinata is not... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chlorophyll fluorescence; Gas exchange; Growth; Light stress; Shade; Tropical tree. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202009000100007 |
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| Bautista,Anna I.N.; Necchi Jr.,Orlando. |
| Three freshwater Rhodophyta species (Audouinella eugenea, A. hermannii and Compsopogon coeruleus) were tested as to their responses (photosynthesis, growth and pigment concentration) to two irradiances (low light, LL, 65 µmol m-2 s-1 and high light, HL, 300 µmol m-2 s-1) and two periods (short time, ST, 4 d, and long time, LT, 28 d). Higher growth rates were consistently observed at LL but significant differences were observed only for A. hermannii. Higher values of photoinhibition at LL were found for the three species, which is consistent with the dynamic photoinhibition as a reversible photoprotective mechanism against high irradiance. Light-induced decreases of effective quantum yield (EQY) were observed in the three species consisting of pronounced... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chlorophyll fluorescence; Growth; Irradiance; Photosynthesis; Pigment; Red algae. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202007000100003 |
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| Registros recuperados: 46 | |
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