Consulta: subjectFacets:"Chlorophyll fluorescence"
Registros recuperados: 46
Data/hora: 13/06/2024 04:35:43

Effects of 5-aminolevulinic acid (ALA)-containing supernatants from selected Rhodopseudomonas palustris strains on rice growth under NaCl stress, with mediating effects on chlorophyll, photosynthetic electron transport and antioxidative enzymes
Provedor de dados: 69
Autores: Nunkaew,Tomorn; Kantachote,Duangporn; Kanzaki,Hiroshi; Nitoda,Teruhiko; Ritchie,Raymond J.
Background: Rice is globally one of the most important food crops, and NaCl stress is a key factor reducing rice yield. Amelioration of NaCl stress was assessed by determining the growth of rice seedlings treated with culture supernatants containing 5-aminolevulinic acid (ALA) secreted by strains of Rhodopseudomonas palustris (TN114 and PP803) and compared to the effects of synthetic ALA (positive control) and no ALA content (negative control). Results: The relative root growth of rice seedlings was determined under NaCl stress (50 mM NaCl), after 21 d of pretreatment. Pretreatments with 1 &amp;#956;M commercial ALA and 10X diluted culture supernatant of strain TN114 (2.57 &amp;#956;M ALA) gave significantly better growth than 10X diluted PP803 supernatant...
Tipo: Journal article
Palavras-chave: 5-Aminolevulinic acid (ALA); Antioxidative enzymes; Chlorophyll fluorescence; Rhodopseudomonas palustris; Rice; Salinity.
Ano: 2014
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582014000100004

PHOTOCHEMICAL AND PRODUCTIVE PERFORMANCE OF YELLOW PASSION FRUIT IRRIGATED IN THE BRAZILIAN SEMIARID
Provedor de dados: 70
Autores: Dutra,Alexson F.; Melo,Alberto S. de; Brito,Marcos E. B.; Suassuna,Janivan F.; Dutra,Wellison F.
ABSTRACT The drought stress is an important factor for crops in areas with low rainfall as in the semiarid regions and affects immediately the physiological processes and plant production. However, irrigation is an essential practice to minimize effects of drought stress since the appropriate management is done it can increase the farm income. This study aimed to analyze the photochemical and productive performance of passion fruit (Passiflora edulis) hybrid ‘BRS Gigante Amarelo' irrigated in a Brazilian semiarid region. It was studied four water replacement rates (33, 66, 100 and 133% of ETo) at field conditions. A randomized block design was used with five replications and the fluorescence of chlorophyll a, yield and fruit quality were evaluated. The...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Passiflora edulis; Drought stress; Chlorophyll fluorescence; Production.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000600901

Response of CO2-starved diatom Phaeodactylum tricornutum to light intensity transition
Provedor de dados: 5
Autores: 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

Laminaria saccharina photosynthesis measured in situ: photoinhibition and xanthophyll cycle during a tidal cycle
Provedor de dados: 5
Autores: 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

Inhibition of microphytobenthic photosynthesis by the herbicides atrazine and diuron
Provedor de dados: 5
Autores: Legrand, Helene; Herlory, Olivier; Guarini, Jean-marc; Blanchard, Gerard; Richard, Pierre.
Atrazine and diuron are two herbicides present in sediments of the intertidal mudflats in the Pertuis Charentais (Atlantic coast, France). They may negatively affect photosynthesis processes in microphytobenthos, the most productive primary producer in these environments. The impact of these herbicides on benthic diatoms was investigated using PAM fluorimetry on natural microalgal communities, once extracted from sediment, by following the variations of the effective quantum yield of PSII (Phi(PSII)) during exposure to atrazine and diuron concentrations in a range 0.1 mu g L-1 (.) 10 mg L-1. No significant effect was noticed for 0.1 mu g L-1 concentrations, but progressive reduction in photosynthetic efficiency, always occurring within 15 min, was...
Tipo: Text
Palavras-chave: Diuron; Atrazine; PAM; Chlorophyll fluorescence; Microphytobenthos.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-3614.pdf

Photosynthetic responses of young cashew plants to varying environmental conditions
Provedor de dados: 86
Autores: Souza,Rogéria Pereira de; Ribeiro,Rafael Vasconcelos; Machado,Eduardo Caruso; Oliveira,Ricardo Ferraz de; Silveira,Joaquim Albenísio Gomes da.
The aim of this study was to characterize gas exchange responses of young cashew plants to varying photosynthetic photon flux density (PPFD), temperature, vapor-pressure deficit (VPD), and intercellular CO2 concentration (Ci), under controlled conditions. Daily courses of gas exchange and chlorophyll a fluorescence parameters were measured under natural conditions. Maximum CO2 assimilation rates, under optimal controlled conditions, were about 13 mmol m-2 s-1 , with light saturation around 1,000 mmol m-2 s-1. Leaf temperatures between 25ºC and 35ºC were optimal for photosynthesis. Stomata showed sensitivity to CO2, and a closing response with increasing Ci. Increasing VPD had a small effect on CO2 assimilation rates, with a small decrease above 2.5 kPa....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Anacardium occidentale; Gas exchange; Chlorophyll fluorescence; Temperature; Vapor-pressure deficit.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2005000800002

Environmental effects on photosynthetic capacity of bean genotypes
Provedor de dados: 86
Autores: Ribeiro,Rafael Vasconcelos; Santos,Mauro Guida dos; Souza,Gustavo Maia; Machado,Eduardo Caruso; Oliveira,Ricardo Ferraz de; Angelocci,Luiz Roberto; Pimentel,Carlos.
Photosynthetic responses to daily environmental changes were studied in bean (Phaseolus vulgaris L.) genotypes 'Carioca', 'Ouro Negro', and Guarumbé. Light response curves of CO2 assimilation and stomatal conductance (g s) were also evaluated under controlled (optimum) environmental condition. Under this condition, CO2 assimilation of 'Carioca' was not saturated at 2,000 µmol m-2 s-1, whereas Guarumbé and 'Ouro Negro' exhibited different levels of light saturation. All genotypes showed dynamic photoinhibition and reversible increase in the minimum chlorophyll fluorescence yield under natural condition, as well as lower photosynthetic capacity when compared with optimum environmental condition. Since differences in g s were not observed between natural and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Phaseolus vulgaris; Chlorophyll fluorescence; Gas exchange; Photosynthesis.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2004000700001

Sugarcane tolerance to ratoon eradication with glyphosate determined by physiological responses
Provedor de dados: 87
Autores: Silva,M.A.; Arantes,M.T.; Oliver,R.; Brunelli,M.C.
This study aimed to evaluate the tolerance of sugarcane cultivars to ratoon eradication under different glyphosate rates by means of physiological responses. Therefore, a trial was carried out in randomized complete blocks with 4 x 4 factorial design (cultivars x rates) totaling 16 treatments with four replicates. The cultivars IAC91-5155, IACSP93-3046, and IAC86-2480 and IAC87-3396 and the glyphosate rates 0 g ha-1; 1,920 g ha-1; 2,400 g ha-1; 2,880 g ha-1 were tested. The variables analyzed were percentage of tiller mortality, quantum efficiency of PSII (Fv/Fm) and SPAD index. The results showed that there are differences among sugarcane cultivars for tiller eradication and for physiological responses with glyphosate different rates. The rate of 2,880 g...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Saccharum spp.; Varieties; Tillers; Chlorophyll fluorescence; SPAD; Herbicide.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582014000100023

Photosynthetic properties of three Brazilian seaweeds
Provedor de dados: 88
Autores: 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 &amp;amp; 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

Chlorophyll fluorescence parameters in populations of two legume trees: Stryphnodendron adstringens (Mart.) Coville (Mimosoideae) and Cassia ferruginea (Schrad.) Schrad. ex DC. (Caesalpinoideae)
Provedor de dados: 88
Autores: Lemos Filho,José P.; Goulart,Maíra F.; Lovato,Maria B.
The aim of this study was to investigate the photosynthetic performance in populations of two legume tree species, Stryphnodendron adstringens (Mimosoideae), typical from Cerrado, and Cassia ferruginea (Caesalpinoideae) from the Atlantic Rain Forest. The photosynthetic traits were assessed by measures of chlorophyll fluorescence in progenies of naturally pollinated plants from three populations of S. adstringens and a population of C. ferruginea. Plants of S. adstringens growing under similar conditions of C. ferruginea plants demanded higher light values for photosynthesis saturation, 600 µmol.m-2.s-1 and 350 µmol.m-2.s-1 respectively, and showed higher intrinsic photosynthetic efficiency of photosystem II, Fv/Fm of 0.814 versus 0.783 in C. ferruginea....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorophyll fluorescence; Legume trees; Population approach; Quantum yield.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042004000300012

Photosynthetic responses of tropical tree species from different successional groups under contrasting irradiance conditions
Provedor de dados: 88
Autores: Ribeiro,Rafael V; Souza,Gustavo M; Oliveira,Ricardo F; Machado,Eduardo C.
This study evaluated the photosynthetic responses of seven tropical trees of different successional groups under contrasting irradiance conditions, taking into account changes in gas exchange and chlorophyll a fluorescence. Although early successional species have shown higher values of CO2 assimilation (A) and transpiration (E), there was not a defined pattern of the daily gas exchange responses to high irradiance (FSL) among evaluated species. Cariniana legalis (Mart.) Kuntze (late secondary) and Astronium graveolens Jacq. (early secondary) exhibited larger reductions in daily-integrated CO2 assimilation (DIA) when transferred from medium light (ML) to FSL. On the other hand, the pioneer species Guazuma ulmifolia Lam. had significant DIA increase when...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorophyll fluorescence; Flexibility response; Functional groups; Gas exchange; High irradiance.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042005000100012

Photosynthetic responses of four tropical tree species grown under gap and understorey conditions in a semi-deciduous forest
Provedor de dados: 88
Autores: Souza,Gustavo M.; Sato,Agnaldo M.; Ribeiro,Rafael V.; Prado,Carlos Henrique B. A.
Leaf CO2 assimilation (A) as a function of photosynthetic photon flux density (Q) or intercellular CO2 concentration (Ci) and chlorophyll fluorescence measurements were carried out on four tropical woody species growing in forest gap and understorey (Bauhinia forficata Link. and Guazuma ulmifolia Lam. as pioneers, and Hymenaea courbaril L. and Esenbeckia leiocarpa Engl. as non-pioneers). Chlorophyll fluorescence indicated similar acclimation capacities of photochemical apparatus to contrasting light environments irrespective to plant species. Maximum CO2 assimilation and quantum yield derived from A/Q curves indicated higher photosynthetic capacity in pioneer than in non-pioneer species in forest gap. However, the differences among species did not show a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Acclimation; Chlorophyll fluorescence; Forest succession; Leaf gas exchange; Photosynthetic response curves.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042010000400002

Photosynthetic efficiency, gas exchange and yield of castor bean intercropped with peanut in semiarid Brazil
Provedor de dados: 91
Autores: 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

Photochemical efficiency in cladodes of ‘Gigante’ cactus pear cultivated under different spacings and organic fertilization
Provedor de dados: 91
Autores: 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

Silicon and boron mitigate the effects of water deficit on sunflower
Provedor de dados: 91
Autores: Neves,Jose M. G.; Aquino,Leonardo A. de; Berger,Paulo G.; Neves,Júlio C. L.; Rocha,Genelício C.; Barbosa,Edimilson A.
ABSTRACT The objective of this study was to evaluate the effect of Ca and Mg silicate and B on the gas exchange, leaf water potential and chlorophyll fluorescence parameters in the sunflower variety Embrapa 122 -V2000 under water stress conditions. The trial was conducted in Red Yellow Latosol with very clayey texture, with contrasting levels of Si and B and subjected to water deficit. The experimental design was randomized blocks in a 24 factorial arrangement, with five replicates. Treatments consisted of the combination of two acidity corrective agents (calcium magnesium silicate and dolomitic limestone), two levels of base saturation (30 and 70%), two levels of B (0.18 mg dm-3 - value available in the soil and 1.20 mg dm-3) and two water regimes (with...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Helianthus annuus; Chlorophyll fluorescence; Gas exchange; Leaf water potential.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662019000300175

Physiological characterization of grapevine rootstocks grown in soil with increasing zinc doses
Provedor de dados: 91
Autores: Zalamena,Jovani; Melo,George W.; Santos,Henrique P.; Silva,Leandro S. da; Fialho,Flavio B.; Brunetto,Gustavo.
ABSTRACTThis study aimed to evaluate the performance of grapevine rootstocks under increasing levels of Zn in the soil and to identify physiological variables that can be used as indicators of excess of Zn in the soil. The rootstocks SO4, Paulsen1103, IAC572, IAC313 and 420A were grown in pots containing soil, which received Zn doses of 0, 20, 40, 80 or 160 mg kg-1 of soil. Dry matter (DM), Zn content in shoots and roots, chlorophyll index, initial fluorescence (Fo), maximum fluorescence (Fm), maximum quantum yield of photosystem II (Fv/Fm), effective quantum yield of photosystem II (Y-II) and non-photochemical quenching (NPQ) were evaluated. The increase of Zn levels in the soil decreased DM in all rootstocks, and IAC572 was superior to the others. The...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Heavy metal; Toxicity; Chlorophyll fluorescence; Vitis spp.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662015001000973

Water salinity, nitrogen and phosphorus on photochemical efficiency and growth of west indian cherry
Provedor de dados: 91
Autores: Sá,Francisco V. da S.; Gheyi,Hans R.; Lima,Geovani S. de; Paiva,Emanoela P. de; Moreira,Rômulo C. L.; Silva,Luderlândio de A.
ABSTRACT The objective of this study was to evaluate the interaction between water salinity and doses of nitrogen and phosphorus on chlorophyll a fluorescence and on the growth of West Indian Cherry (‘acerola’) plants in the initial growth stage. The research was carried out in a protected environment, in lysimeters filled with Regolithic Neosol of loamy clay texture and low initial phosphorus content. The experiment was conducted in a randomized block design, arranged in a factorial scheme with two factors, five levels of electrical conductivity of the irrigation water - ECw (0.6, 1.4, 2.2, 3.0 and 3.8 dS m-1) and four proportions of the recommendation of phosphorus/nitrogen - P/N (100:100, 140:100, 100:140 and 140:140% P/N of recommendation), with three...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorophyll fluorescence; Saline stress; Fertilization; Malphigia emarginata.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000300158

SENSITIVITY TO ENVIRONMENTAL STRESS OF PRATA,JAPIRA AND VITÓRIA BANANA CULTIVARS PROVEN BY CHLOROPHYLL a FLUORESCENCE
Provedor de dados: 94
Autores: SANTOS,PRISCILA NOBRES DOS; SILVA,DIOLINA MOURA; GALLON,CAMILLA ZANOTTI; VENTURA,JOSÉ AIRES.
ABSTRACT  This study aimed to evaluate the physiological responses to environmental stress during pre- and post-harvest of the following banana cultivars: Prata (AAB), Japira (AAAB) and Vitoria (AAAB). Analyses were carried out on young plants at vegetative stage (daughter-plant) and adult plants at reproductive stage (motherplant). The experimental design was completely randomized. In the in vivo pre-harvest analysis were used seven replications, in a factorial scheme (3x2x2), three cultivars and two stages (vegetative and reproductive) and two collection periods (March and June). For the analysis of post-harvest quality were used five replications in a factorial design (3x2x5), corresponding to three cultivars, two development stages and five periods of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Musa spp; Chlorophyll fluorescence; Pigments; Lipid peroxidation; Post-harvest quality.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452017000200203

Seasonal changes in the photosynthetic performance of two evergreen Nothofagus species in south central Chile
Provedor de dados: 97
Autores: ZÚÑIGA,RAFAEL; ALBERDI,MIREN; REYES-DÍAZ,MARJORIE; OLIVARES,ERICK; HESS,SUSAN; BRAVO,LEÓN A; CORCUERA,LUIS J.
The evergreen Nothofagus dombeyi and Nothofagus nitida are important members of the temperate Chilean rainforest. They seldom grow together in nature. Nothofagus nitida is more susceptible to excess light and drought than N. dombeyi. We postulate that the different properties of the photosynthetic apparatus under common garden conditions of these species could explain their contrasting habitat preferences. The two species growing in a common garden in south central Chile were studied. The optimal photochemical efficiency (Fv/Fm) of both species remained within normal values (»0.8) with the exception of a decrease in N. dombeyi at midday in summer, suggesting reversible reduction in photochemical efficiency of photosystem II (PSII). During summer the...
Tipo: Journal article
Palavras-chave: Chlorophyll fluorescence; Photosynthesis; Nothofagus dombeyi; Nothofagus nitida; Xanthophyll cycle.
Ano: 2006
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2006000400008

Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern Spain
Provedor de dados: 97
Autores: 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

Photosynthetic performance of Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae) in a high-elevation site of the Andes of central Chile
Provedor de dados: 97
Autores: 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

Photochemical efficiency of PSII and photoprotective pigments in seedlings and adults of two Proteaceae with different shade tolerance from the Chilean temperate rain forest
Provedor de dados: 97
Autores: ALBERDI,MIREN; REYES-DÍAZ,MARJORIE; ZÚÑIGA,RAFAEL; HESS,SUSAN; BRAVO,LEÓN A; CORCUERA,LUIS J.
The seasonal variation in energy quenching parameters of photosystem II and photoprotective pigments were studied in seedlings and adults of two Proteaceae: a shade-intolerant species (Embotrium coccineum J.R. et G. Forster) and a shade-tolerant species (Lomatia ferruginea (Cav.) R. Br.). We postúlate that the shade intolerant species favors photochemical energy driven processes (mainly C0(2) assimilation) while the shade tolerant species exhibits higher non-photochemical energy dissipation under unfavorable conditions. Moreover, the shade tolerant species presents lower seasonal variations in these parameters that the shade intolerant species. Differences in energy dissipation should be more evident in seedlings than adults because of their contrasting...
Tipo: Journal article
Palavras-chave: Chlorophyll fluorescence; Lutein; Photosynthesis; Photoprotective pigments; Xanthophyíls cycle.
Ano: 2009
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2009000300006

Chlorophyll fluorescence of the testa of Brassica oleracea seeds as an indicator of seed maturity and seed quality
Provedor de dados: 63
Autores: Jalink,H.; Frandas,A.; Schoor,R. van der; Bino,J.B.
Chlorophyll fluorescence of the testa of seeds is proposed as a non-invasive method for the determination of maturity and quality of seeds. In this study cabbage seeds (Brassica oleracea) were sorted individually based on the chlorophyll fluorescence signals into four subsamples labeled with respect to their chlorophyll fluorescence signal (low, medium, high and very high). The results show that the magnitude of the chlorophyll fluorescence signal was inversely related to the quality of the seeds, expressed as germination %, normal seedling %, germination rate (T50) and uniformity of germination (T75-T25). The seed lot could be improved from 90 to 97% normal seedlings by sorting out 13% of the seeds with very high chlorophyll fluorescence signals....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Maturation; Chlorophyll fluorescence; Cabbage seed; Sorting; Quality.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161998000500016

Salt stress induced damages on the photosynthesis of physic nut young plants
Provedor de dados: 63
Autores: 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

Respiratory quotient: innovative method for monitoring ‘Royal Gala’ apple storage in a dynamic controlled atmosphere
Provedor de dados: 63
Autores: Weber,Anderson; Brackmann,Auri; Both,Vanderlei; Pavanello,Elizandra Pivotto; Anese,Rogério de Oliveira; Thewes,Fabio Rodrigo.
Apples (Malus domestica, Borkh.) which are not stored at low temperature or in a properly controlled atmosphere (CA) may have a high metabolic rate during the postharvest stage resulting in losses in quality. The aim of this study was to evaluate the quality of ‘Royal Gala’ apple fruit stored in accordance with a new method of dynamic controlled atmosphere (DCA).The respiratory quotient (RQ) was monitored at two temperatures which were then compared using a commercially available technology based on chlorophyll fluorescence DCA (DCA-CF) and static CA. Ethylene production and respiration rates were lower in apples stored in DCA than in CA, as a result of lower 1-aminocyclopropane-1-carboxylate oxidase activity, especially in apples stored in DCA-RQ2. Flesh...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ethanol; Ethylene; Physiological disorders; Chlorophyll fluorescence.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162015000100028

ผลของการฉีดพ่นสเปอร์มิดีนต่อคลอโรฟิลล์ฟลูออเรสเซนส์ ปริมาณโพรลีน และการรั่วไหลของอิเล็กโทรไลต์ของใบข้าวเหนียวดำภายใต้สภาวะเค็ม
Provedor de dados: 106
Autores: Panya Madi; Sumitahnun Chantaburi; Jirawat Sanitchon; wattana pattanagul; Piyatida Theerakulpisut.
Saline soil is a major problem that affects growth and productivity of rice. Spermidine (Spd), a member of polyamine (PA), is a plant growth regulator playing essential roles in protecting many crop plants under salinity stress. The objective of this study was to explore the roles of exogenous spermidine in protecting salt-stressed rice plants by evaluating its effects on three physiological indicators of plant stress. Two black glutinous rice cultivars (Oryza sativa L. spp. indica), including cv.Gs.no.00621(salt tolerant) and cv. LLR-039 (salt sensitive) were grown in potted soils until early booting stage. The plants were then arranged into three treatment groups including 1) control 2) 25 mM NaCl and 3) foliar application with 1 mM Spd prior to exposure...
Tipo: PhysicalObject
Palavras-chave: Black glutinous rice; Salt stress; Spermidine; Electrolyte leakage; Sticky rice; Chlorophyll fluorescence; Proline content; ข้าวเหนียวดำ; ดินเค็ม; สเปอร์มิดีน; การรั่วไหลของอิเล็กโทรไลต์; สภาวะเครียด; โพรลีน; การฉีดพ่นทางใบ; ความทนเค็ม.
Ano: 2012
URL: http://anchan.lib.ku.ac.th/agnet/handle/001/5420

Differential response of photosynthetic activity, leaf nutrient content and yield to long-term drought in cacao clones
Provedor de dados: 109
Autores: 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

PHOTOSYNTHETIC PERFORMANCE AND LEAF WATER POTENTIAL OF GULUPA (Passiflora edulis Sims, PASSIFLORACEAE) IN THE REPRODUCTIVE PHASE IN THREE LOCATIONS IN THE COLOMBIAN ANDES
Provedor de dados: 37
Autores: 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

PHOTOSYNTHETIC RESPONSE TO LOW AND HIGH LIGHT OF CACAO GROWING WITHOUT SHADE IN AN AREA OF LOW EVAPORATIVE DEMAND
Provedor de dados: 37
Autores: 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

Different physiological responses under drought stress result in different recovery abilities of two tropical woody evergreen species
Provedor de dados: 39
Autores: 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

Vitality of lichens under different light climates in an Araucaria forest (Pró-Mata RS, South Brazil) as determined by chlorophyll fluorescence
Provedor de dados: 39
Autores: 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

Ecophysiological performance of a threatened shrub under restored and natural conditions in a harsh tropical mountaintop environment
Provedor de dados: 39
Autores: Castro,Silvana A. B.; Sá,Camila E. M.; Mourão,Fabiana A.; Duarte,Heitor M.; Fernandes,G. Wilson; Lemos-Filho,José P.
Ecophysiological responses of plants are useful for monitoring the success of ecological restoration projects that target species conservation. In this study we evaluated the ecophysiological traits of individuals of Chamaecrista semaphora from a natural population and from a site under restoration. Water potential and chlorophyll a fluorescence parameters were measured both in adult and young plants of the two populations. No difference in water potential was found between sites, but individuals in the restored site had higher water potential at predawn. Adults in the natural site presented lower daily values of potential quantum yield, indicating the occurrence of photoinhibition. Individuals in the restored site also presented higher maximum relative...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorophyll fluorescence; Ecological restoration; Endangered species; Plant performance; Rupestrian grasslands.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062016000100017

Copper Stress on Photosynthesis of Black Mangle (Avicennia germinans)
Provedor de dados: 42
Autores: GONZALEZ-MENDOZA,DANIEL; GIL,FRANCISCO ESPADAS y; ESCOBOZA-GARCIA,FERNANDO; SANTAMARIA,JORGE M.; ZAPATA-PEREZ,OMAR.
The effects of copper toxicity on the photosynthetic activities of Avicennia germinans was investigated using two CuSO4 concentrations (0.062 and 0.33 M) added in Hoagland's solution in an aerated hydroponic system. Photosynthesis and chlorophyll fluorescence were measured after 30 h of copper stress. Results obtained in this study show that increasing levels of Cu+2 of 0.062 and 0.33 M Cu+2 resulted in a general reduction of the stomatal conductance (28 and 18%, respectively) and 100% of inhibition of net photosynthesis. Additionally, at these concentrations of Cu+2, reductions of chlorophyll fluorescence parameters were also observed. These changes suggested that the photosynthetic apparatus of Avicennia germinans was the primary target of the Cu+2...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Avicennia germinans; Chlorophyll fluorescence; Copper; Photosystem II; Photosynthesis.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652013000200665

The effects of sooty mold on photosynthesis and mesophyll structure of mahogany (Swietenia macrophylla King., Meliaceae)
Provedor de dados: 53
Autores: Lemos Filho,José Pires de; Paiva,Élder Antônio Sousa.
The aim of present study was to evaluate the effects of the sooty mold on anatomy and photochemical activity of mahogany (Swietenia macrophylla) leaves. The photochemical features of shade-developed leaves with or without sooty mold were compared to those of sun leaves using chlorophyll a fluorescence measurements. Leaf anatomy was also evaluated using conventional techniques. The degree of blockage of the photosynthetic active photon flux density (PPFD) by sooty mold and its effect on photochemistry were evaluated. Sun leaves showed thick mesophyll with palisade parenchyma disposed in a uniseriate layer, whereas shade leaves showed narrow mesophyll, independently of sooty mold presence. The effective quantum yield (deltaF/Fm') and the apparent electron...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorophyll fluorescence; Leaf anatomy; Photochemical activity.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052006000100003

Can the critical temperature for photochemical damage in common bean plants be changed after a drought event?
Provedor de dados: 53
Autores: 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

Effects of n-propyl gallate on photosynthesis and physiological parameters in Dunaliella salina are affected by stressful conditions
Provedor de dados: 61
Autores: Einali,Alireza; Shariati,Mansour.
We studied the effects of n-propyl gallate, which is a plastid terminal oxidase inhibitor involved in chlororespiration, on photosynthesis and physiological parameters in Dunaliella salina grown under different salinities and under low or high irradiance using chlorophyll a fluorescence transient measurements and pigment analysis. The inhibitor up to 1 mM had an additive significant effect on the photosynthetic efficiency in the cell suspensions grown under low salinity and irradiance. However, in the presence of high n-propyl gallate concentration (4 mM), there was a negative effect on all physiological aspects. In contrast, this high concentration of the inhibitor could enhance efficiency of electron transport and growth parameters under high irradiance....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorophyll fluorescence; Dunaliella salina; Light intensity; Photosynthesis; Salt stress.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202012000300006

Growth, photosynthesis and leaf water potential in young plants of Copaifera langsdorffii Desf. (Caesalpiniaceae) under contrasting irradiances
Provedor de dados: 61
Autores: Ronquim,Carlos Cesar; Prado,Carlos Henrique B. A.; Souza,João Paulo de.
Growth and leaf nutrient content were compared in young potted plants of Copaifera langsdorffii in sunny and shaded areas without water stress. Besides, carbon assimilation and leaf water relations were evaluated by net photosynthesis, potential photochemical efficiency and leaf water potential during daily courses in dry and rainy periods under natural conditions in both contrasting irradiances. Higher values of total biomass, height and leaf area occurred in sunny than in shaded area. On the other hand, all young plants survived in shade under natural water stress probably by reason of fast and intense biomass accumulation in favor of roots in early development. There was no significant difference about nutrient concentration in leaves between plants...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cerrado; Biomass partitioning; Chlorophyll fluorescence; Leaf gas exchange; Irradiance; Sunflecks.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202009000300004

Light as an indicator of ecological succession in brazilwood (Caesalpinia echinata Lam.)
Provedor de dados: 61
Autores: 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

Photoacclimation in three species of freshwater red algae
Provedor de dados: 61
Autores: 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

Some aspects of citrus ecophysiology in subtropical climates: re-visiting photosynthesis under natural conditions
Provedor de dados: 61
Autores: Ribeiro,Rafael V.; Machado,Eduardo C.
In this review we re-visit and discuss the current knowledge on ecophysiology of citrus trees, addressing the influence of environmental conditions on citrus photosynthesis. Knowledge of physiological responses of citrus trees to their surrounding environment is essential in order to improve crop production and plant development, both being consequences of appropriate horticultural management in citrus orchards. In this context, citrus photosynthesis is addressed as the primary source of carbon and energy for plant growth and development. The photosynthetic activity on both a daily and a seasonal scale is reviewed, taking into consideration the physiological aspects related to seasonal variation of photochemical and biochemical activities, stomatal...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Carbohydrate; Citrus; Chlorophyll fluorescence; Gas exchange; Seasonality.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202007000400009

High temperature effects on the response of photosynthesis to light in sweet orange plants infected with Xylella fastidiosa
Provedor de dados: 61
Autores: Ribeiro,Rafael Vasconcelos; Machado,Eduardo Caruso; Oliveira,Ricardo Ferraz de; Pimentel,Carlos.
The objective of this study was to evaluate the high temperature effects on the response of photosynthesis to light in sweet orange plants infected with Xylella fastidiosa. This vascular bacterium is the causal agent of the citrus variegated chlorosis that causes severe economical losses to the Brazilian citrus industry. The responses of the photosynthetic oxygen evolution and the parameters related to chlorophyll a fluorescence to the increase in light intensity were evaluated at 35ºC and 45ºC in both healthy and infected leaf discs. The increase in temperature affected the photosynthetic apparatus of both healthy and infected plants, although infected plants showed higher photochemical sensitivity at the higher temperature (e.g. in the potential quantum...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorophyll fluorescence; Citrus sinensis; Light response curve; Photosynthesis; Temperature; Xylella fastidiosa.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202003000200004

Photo-oxidative stress in coconut seedlings: early events to leaf scorching and seedling death
Provedor de dados: 61
Autores: Naresh,Kumar S.; Kasturi Bai,K.V.
Experiments were conducted on coconut seedlings to delineate events of photo-oxidative stress damage. Studies on chlorophyll fluorescence indicated a clear case of excess light energy under high light conditions causing stress to coconut seedlings raised under coconut palms. Quantum yield of photo-chemistry of leaflets exposed to high light was significantly less than those under shade. Seedlings exposed to high light and then shifted to shade have shown significant improvement in quantum yield. Excess light energy harvested by chlorophyll antenna caused high non-photochemical quenching resulting in production of biologically toxic super oxide, hydrogen peroxide and hydroxyl radicals. It is apparent that photoinhibition of photosynthesis takes place due to...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cocos nucifera; Chlorophyll fluorescence; Oxidative stress; Photosynthesis; Lipid peroxidation; Gas exchange; Proteins.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202009000300006

Evaluation of fertilization with uncoated urea and 3,4-dimethylpyrazole phosphate (DMPP)-coated urea on nitrogen leaching and rose (Rosa spp.) yield
Provedor de dados: 117
Autores: García-Castro,Alexandra; Restrepo-Díaz,Hermann.
The negative impact of N over-fertilization has acquired importance in rose (Rosa spp.) growers in Colombia. The nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) has been considered a valuable alternative to diminish the N losses by leaching and to enable more efficient N use efficiency in crops. The objective of the present work was to study the effect of DMPP on the mineral N (NH4+- N and NO3--N) content in soil and water leaching, and physiological characteristics of rose plants. A greenhouse experiment was performed for 10 wk. Four-year-old 'Charlotte' rose cultivars grafted on 'Natal Briar' were grown in soil and fertirrigated daily with a complete nutrient solution containing 170 mg N L-1. Two N fertilizers (uncoated urea [UA], and urea...
Tipo: Journal article
Palavras-chave: Chlorophyll fluorescence; Leaf nitrogen concentration; Nitrate leaching; Nitrogen use efficiency.
Ano: 2013
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392013000200011

Chlorophyll fluorescence response of Pinus radiata clones to nitrogen and phosphorus supply
Provedor de dados: 118
Autores: 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

Photosynthetic capacity of 'Niagara Rosada' grapes grown under transparent plastic covering
Provedor de dados: 65
Autores: 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

Photosynthetic behaviour during the leaf ontogeny of rubber tree clones[Hevea brasiliensis (Wild. ex. Adr. de Juss.) Muell. Arg.], in Lavras, MG
Provedor de dados: 64
Autores: Miguel,Aurélio Antas; Oliveira,Luiz Edson Mota de; Cairo,Paulo Araquém Ramos; Oliveira,Davi Melo de.
This work proposed to investigate changes in the photosynthetic behavior during the leaf ontogeny of the during the leaf development. Up to the 32nd day of leaf age (stage B2), the net photosynthesis was negative due to the inefficiency of the photosynthetic system, and this fact was justified by the following factors: low chlorophyll content, less stomatal conductance, high rubber tree clones PB 235, RRIM 600 and GT 1, in Lavras, MG. The experiment was performed in 2004, between May and July, under field conditions, at the Universidade Federal de Lavras. During the leaf ontogeny, the following characteristics were evaluated: chlorophyll content, gaseous exchanges and chlorophyll fluorescence. The clones presented similar profiles of alterations in the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Rubber tree; Photosynthesis; Gaseous exchanges; Chlorophyll fluorescence.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542007000100014