|
|
|
| Registros recuperados: 46 | |
|
| |
|
|
| 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 |
| |
|
|
| Bown,Horacio E; Mason,Euan G; Clinton,Peter W; Watt,Michael S. |
| Chlorophyll fluorescence responses to a factorial combination of nitrogen (N) and phosphorus (P) supply were measured in five clones of Pinus radiata cultivated in a greenhouse over twenty-four months. Chlorophyll fluorescence measurements were taken at months six (5 clones, 182 plants), nine (2 clones, 68 plants) and eighteen (2 clones, 48 plants). Plant growth in stem diameter, height, leaf area, fascicle mass, length and diameter were found to significantly increase with N and, to a lesser extent, P additions; and these values were greatest when both N and P were combined. Plant growth and fascicle size also varied significantly across clones and were generally consistent with the genotypic growth responses that were observed in the field. Dark (Fv /... |
| Tipo: Journal article |
Palavras-chave: Chlorophyll fluorescence; Quantum efficiency of PSII; Electron transport; Genotype; Nutrient limitation. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202009000300012 |
| |
|
|
| Brito,Cleiton F. B.; Donato,Sérgio L. R.; Arantes,Alessandro de M.; Donato,Paulo E. R.; Silva,João A. da. |
| ABSTRACT The objective of this study was to determine the photochemical efficiency of ‘Gigante’ cactus pear cultivated under different spacings and bovine manure doses in the semi-arid region. The experiment was conducted in a randomized block design in a 4 x 3 x 7 factorial scheme, with three replicates. The first factor consisted of four doses of organic fertilization (0, 30, 60 and 90 Mg ha-1 year-1 of bovine manure), the second one, of three spacings (1.0 x 0.5, 2.0 x 0.25 and 3.0 x 1.0 x 0.25 m) and the third one of seven reading times (6, 8, 10, 12, 14, 16 and 18 h). Chlorophyll a fluorescence readings were taken in cactus pear cladodes in the dry and rainy seasons using a pulse-modulated fluorometer. Cladodes of ‘Gigante’ cactus pear cultivated... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Opuntia; Arrangement of plants; Chlorophyll fluorescence. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000500338 |
| |
|
|
| 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 |
| |
|
| |
|
|
| Chaloub,Ricardo M.; Reinert,Fernanda; Nassar,Cristina A. G.; Fleury,Beatriz G.; Mantuano,Dulce G.; Larkum,Anthony W. D.. |
| Photosynthetic performance of distinct marine macroalgae, Ulva fasciata Delile (green alga), Lobophora variegata (J. V. Lamouroux) Womersley ex E. C. Oliveira (brown alga), and Plocamium brasiliensis (Greville) M. A. Howe & W. R. Taylor (red alga), were compared using a pulse amplitude-modulated fluorometer. The maximum quantum yield (Fv/Fm) ranged from 0.80 to 0.51, and the lowest value was found in P. brasiliensis. Under 400 µmol photons m-2 s-1 irradiance, the highest value of photochemical quenching (qP = 0.92 ± 0.13) was observed for U. fasciata. The red alga P. brasiliensis dissipated high amounts of excitation energy (qN = 0.56 ± 0.09), resulting in relatively low values for the effective quantum yield of PS-II (0.23 ± 0.04), as well as for... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chlorophyll fluorescence; Lobophora variegata; Plocamium brasiliensis; Ulva fasciata. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042010000200017 |
| |
|
|
| Deus,Bruna Corrêa da Silva de; Figueiredo,Fábio Afonso Mazzei Moura de Assis; Almeida,Luciana Venturotti Braun de; Ferraz,Tiago Massi; Martins,Amanda Oliveira; Rodrigues,Weverton Pereira; Viana,Leandro Hespanhol; Esteves,Barbara dos Santos; Campostrini,Eliemar. |
| ABSTRACT: New techniques in tropical regions such as use of transparent plastic covering (TPC), have been employed in grapes to avoid the wetting leaves and fruits, which can reduce the occurrence of fungal diseases, reduce the use of sprays, and reduce damage caused by hail and high winds. TPC may significantly affect the photosynthetic rates of grapevines cultivated in tropical regions, and thus have strong effects on plant productivity and improve fruit quality. However, in the North of Rio de Janeiro region there are lacks of studies related to TPC effects on photosynthetic capacity. The objective of this study was to evaluate the photosynthetic capacity in 'Niagara Rosada' vines grown under TPC and without transparent plastic covering (WTPC). The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Photosynthesis; Chlorophyll fluorescence; Vitisla brusca; Covered system. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782016000600950 |
| |
|
| |
|
|
| Dutra,Wellison F.; Melo,Alberto S. de; Dutra,Alexson F.; Brito,Marcos E. B.; Filgueiras,Luanna M. B.; Meneses,Carlos H. S. G.. |
| ABSTRACT To evaluate the photosynthetic efficiency, gas exchange and yield of castor bean intercropped with peanut under Brazilian semiarid conditions, a field experiment was set up with six treatments and four replicates arranged in a randomized block design. The experiment consisted of the cultivation of castor bean ‘BRS Energia’ in a monocrop system and intercropped with peanut ‘BR 1’. One treatment was formed by monocropped castor bean and the others by the castor bean intercropped with peanut with different intercrop establishment times, i.e. peanut sowing times (0, 10, 15, 20 and 25 days after castor bean sowing). The castor bean photosynthetic and carboxylation efficiencies were higher in the intercrop system with a 25-day interval between sowings.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chlorophyll fluorescence; Photosynthesis; Ricinus communis L.; Yield. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000200106 |
| |
|
| |
|
|
| FIGUEROA,FÉLIX L.; VIÑEGLA,BENJAMÍN. |
| The effects of solar ultraviolet (UV) radiation during daily cycles on photosynthesis and two key enzymes involved in carbon incorporation, the carbonic anhydrase, and in inorganic nitrogen reduction, the nitrate reductase, of macroalgae from southern Spain are presented. During daily cycles, photoinhibition in several intertidal macroalgae, expressed as decrease in the effective quantum yield from the morning to noon time, was linearly dependent on the daily integrated irradiance. However, recovery, expressed as the increase in the effective quantum yield from noon to the afternoon, presented a different pattern; full recovery was found below daily integrated irradiance of 1.0 x10(4) kJ m-2. However, recovery reached only 50 % at higher irradiances. The... |
| Tipo: Journal article |
Palavras-chave: Carbonic anhydrase; Chlorophyll fluorescence; Effective quantum yield; Nitrate reductase; Ultraviolet radiation. |
| Ano: 2001 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000200003 |
| |
|
|
| 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 |
| |
|
| |
|
|
| Gevaert, F; Creach, A; Davoult, D; Migne, A; Levavasseur, G; Arzel, Pierre; Holl, Ac; Lemoine, Y. |
| Photosynthetic activity in thalli of Laminaria saccharina (Lamouroux) was followed in situ in the upper subtidal zone of a Northern Brittany rocky shore (Roscoff, France), using a submersible pulse amplitude modulated (PAM) fluorometer. Two fluorescence parameters, the effective quantum yield of photosystem II (Phi(PSII)) and the relative electron transport rate (rETR), were estimated at various stages of a tidal cycle from 10:00 to 18:30 h, and different light conditions due to variations of water depth and position of the sun. The Phi(PSII) decreased strongly during the ebb tide, essentially due to a drop in the maximal fluorescence level for light-adapted samples (F-m'). This was the result of increasing non-photochemical quenching (NPQ). Algae totally... |
| Tipo: Text |
Palavras-chave: Laminaria saccharina; Photoprotection; Xanthophyll cycle; Chlorophyll fluorescence; Diurnal tidal cycles; Diving PAM. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00000/10191/7592.pdf |
| |
|
| |
|
|
| 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 |
| |
|
|
| Heydarizadeh, Parisa; Boureba, Wafaa; Zahedi, Morteza; Huang, Bing; Moreau, Brigitte; Lukomska, Ewa; Couzinet-mossion, Aurelie; Wielgosz-collin, Gaetane; Martin-jezequel, Veronique; Bougaran, Gael; Marchand, Justine; Schoefs, Benoit. |
| In this study, we investigated the responses of Phaeodactylum tricornutum cells acclimated to 300 mu mol m(-2) s(-1) photon flux density to an increase (1000 mmol m(-2) s(-1)) or decrease (30 mmol m(-2)s(-1)) in photon flux densities. The light shift occurred abruptly after 5 days of growth and the acclimation to new conditions was followed during the next 6 days at the physiological and molecular levels. The molecular data reflect a rearrangement of carbon metabolism towards the production of phosphoenolpyruvic acid (PEP) and/or pyruvate. These intermediates were used differently by the cell as a function of the photon flux density: under low light, photosynthesis was depressed while respiration was increased. Under high light, lipids and proteins... |
| Tipo: Text |
Palavras-chave: Phaeodactylum tricornutum; Carbon metabolism; Light regulation; Photosynthesis; Chlorophyll fluorescence; Pyruvate hub. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00395/50620/52341.pdf |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
| Registros recuperados: 46 | |
|
|
|
