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	Provedor de dados 93 (48) Autor BARROS,EVERALDO GONÇALVES DE (2) CAMBRAIA,JOSÉ (2) CANO,MARCO ANTONIO OLIVA (2) DA MATTA,FÁBIO M. (2) ENÉAS-FILHO,JOAQUIM (2) GOMES-FILHO,ENÉAS (2) MAGALHÃES,PAULO CÉSAR (2) MOREIRA,FÁTIMA MARIA SOUZA (2) MOREIRA,MAURILIO ALVES (2) OLIVEIRA,MARIA GORETI DE ALMEIDA (2) PIOVESAN,NEWTON DENIZ (2) PRISCO,JOSÉ TARQUÍNIO (2) SIQUEIRA,JOSÉ OSWALDO (2) SOARES,CLÁUDIO ROBERTO FONSÊCA SOUSA (2) ACCIOLY,ADRIANA MARIA DE AGUIAR (1) ALVARENGA,AMAURI ALVES DE (1) ALVES,JOSÉ DONIZETI (1) AMARAL,JOSÉ A.T. (1) AMARAL,LOURDES ISABEL VELHO DO (1) ARGENTA,GILBER (1) Mais... Palavra-chave Aminoácidos (2) Carbohydrates (2) Dormência (2) Endosperm (2) Lipids (2) Lycopersicon esculentum (2) Potencial hídrico (2) Proteins (2) Vigna unguiculata (2) Zea mays (2) 2-D gel electrophoresis (1) ABA (1) Absorção (1) Acca sellowiana (1) Aclimatação (1) Al detoxification (1) Aldeídos (1) Alternative oxidase (1) Alternative respiratory pathway (1) Amino acids (1) Mais... Tipo do documento Info:eu-repo/semantics/article (47) Info:eu-repo/semantics/other (1) Ano 2001 (31) 2000 (17) País Brazil (48) Idioma Inglês (28) Português (20)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 48 Primeira ... 1 2 3 ... Última Concentration of photosynthetic pigments and chlorophyll fluorescence of mahogany and tonka bean under two light environments 93 GONÇALVES,JOSÉ FRANCISCO DE CARVALHO; MARENCO,RICARDO ANTONIO; VIEIRA,GIL. This study was carried out in a plantation of a degraded area in Central Amazon, Brazil, in order to assess environmental light effects on leaf pigment concentrations and chlorophyll a fluorescence in mahogany (Swietenia macrophylla King) and tonka bean (Dipteryx odorata Aubl. Willd). Three-year old saplings were grown in an open site (sun) with maximum radiation of approximately 2000 mumol m-2 s-1 and under the shade of a Ochroma pyramidale (Cav. ex Lam. Urb) canopy. A leaf area index of 2.46 was optically determined for the Ochroma foliage with 13% of full sunlight (maximum radiation about 260 mumol m-2 s-1). Carotenoid and chlorophyll concentrations were spectrophotometrically determined. Initial (Fo), maximum (Fm) and variable fluorescence (Fv) were... Tipo: Info:eu-repo/semantics/article Palavras-chave: Carotenoid; Dipteryx odorata; Swietenia macrophylla; Tropical species. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000200004 Pectin degradation in ripening and wounded fruits 93 HUBER,DONALD J.; KARAKURT,YASAR; JEONG,JIWON. Pectin depolymerization during fruit ripening has been shown to be largely due to pectinolytic enzymes, including polygalacturonases (E.C. 3.2.1.15) and pectinmethylesterases (E.C. 3.2.1.11). Studies have shown that these enzymes are not the primary determinants of softening, although participation in texture changes during the late stages of ripening seems evident. Pectin depolymerization differs significantly between various fruit types, notably avocado and tomato, even though levels of extractable PG activity in these fruits are similar. Collective evidence indicates that the activities of some cell wall enzymes are restricted in vivo, with maximum hydrolytic potential expressed only in response to tissue disruption or wounding. In contrast, other... Tipo: Info:eu-repo/semantics/article Palavras-chave: Apoplast; Lipids; Membranes; Oligogalacturonides; Pectin fragments; Polygalacturonase; Radical oxygen species. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000200009 Expressão gênica diferencial durante déficit hídrico em soja 93 CASAGRANDE,ELAINE CRISTINA; FARIAS,JOSÉ RENATO BOUÇAS; NEUMAIER,NORMAN; OYA,TETSUJI; PEDROSO,JÚLIO; MARTINS,POLYANA KELLY; BRETON,MICHÈLLE CLAIRE; NEPOMUCENO,ALEXANDRE LIMA. Tolerância à seca em plantas não é uma característica simples, mas sim um complexo de mecanismos que trabalham em conjunto ou isoladamente para evitar ou tolerar períodos de déficit hídrico. Genótipos que diferem em tolerância ao déficit hídrico devem apresentar diferenças qualitativas e quantitativas na expressão gênica quando submetidos a períodos de seca. Três cultivares de soja (BR-4, BR-16 e MG/BR-46 Conquista), com respostas contrastantes ao déficit hídrico, foram estudadas com o uso da técnica "Differential Display" (DD) para identificar e isolar genes que podem apresentar diferenças de expressão durante períodos de seca entre os genótipos estudados. Um total de 84 fragmentos de DNAc diferencialmente expressos foram detectados. Trinta e cinco... Tipo: Info:eu-repo/semantics/article Palavras-chave: RNA mensageiro; Differential Display; Seca; Expressão gênica; NADH Desidrogenase; Ativador de Transcrição. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000200006 Isolation and partial characterization of a lectin from Bauhinia pentandra (bong) vog. Ex. Steua. 93 SILVA,ANDRÉ LUIS COELHO DA; HORTA,ANA CECÍLIA GÓES; MOREIRA,RENATO DE AZEVEDO. Bauhinia pentandra (Bong) Vog. ex. Steua seeds were investigated with respect to phenologic aspects (size, mass, hilum and length) and with respect to their chemical composition. The total nitrogen content of the seed flour was determined, and the flour was extracted in different pH values. A lectin was isolated from the seeds by Sepharose-4B affinity chromatography. The homogeneity of the lectin was demonstrated by SDS-PAGE in the presence of beta-mercaptoethanol. Only one protein band with an apparent molecular mass of 30 kDa was found. The B. pentandra lectin showed a carbohydrate specificity for D-galactose, a requirement for divalent metal cations (Ca2+ and Mn2+) for full activity and amino acid composition with a high content of aspartic acid,... Tipo: Info:eu-repo/semantics/article Palavras-chave: Bauhinia; Leguminosae; Phytohemagglutinin; Seed protein; D-galactose. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000300002 Influence of photoperiod on the accumulation of allantoin in comfrey plants 93 CASTRO,ANA HORTÊNCIA FONSÊCA; YOUNG,MARIA CLÁUDIA MARX; ALVARENGA,AMAURI ALVES DE; ALVES,JOSÉ DONIZETI. In order to evaluate the influence of photoperiod on the accumulation of allantoin in comfrey (Symphytum officinale L.), a well known medicinal plant, an experiment was conducted during July and August, 1998. Cuttings obtained from 90 day old plants were submitted to four photoperiods (8, 12, 16 and 20 hours). After 60 days, allantoin content in roots and rhizomes was evaluated. The results showed that increases in photoperiod promoted an increment in the average content of allantoin in roots (0.06%, 0.303%, 1.213% and 4.78%). On the other hand, in rhizomes, allantoin accumulation decreased (9.65%, 7.14%, 0.55%) when the photoperiod was increased from 8 to 12 and 16 hours, respectively, stabilizing on a 20-hour photoperiod (0.53%). Plants cultivated under... Tipo: Info:eu-repo/semantics/article Palavras-chave: HPLC; Medicinal plant; Secondary metabolism; Symphytum officinale; Ureides. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000100006 Analysis of proteins associated with storage root formation in cassava using two-dimensional gel electrophoresis 93 CABRAL,GLAUCIA B.; CARVALHO,LUIZ J.C.B.. Two-dimensional gel electrophoresis analysis was performed on adventitious and storage root in cassava (Manihot esculenta Crantz). Adventitious root lacking swelling formation and swelled storage root were obtained from the accession WU104 grown in the green house of the Department of Biology in Washington University in St. Louis (MO-USA). Saline buffer-soluble proteins were extracted, separated in a high-resolution 2-D electrophoresis system, visualized with silver staining gel procedure, and digital image generate for further analysis. Quantitative and qualitative protein spots analysis was performed with a computer assisted image software system. Results revealed large variation in the complexity of the gel protein profile between the two root systems.... Tipo: Info:eu-repo/semantics/article Palavras-chave: Cassava; Manihot esculenta; Storage root; 2-D gel electrophoresis; Proteins. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000100005 Influence of mechanical root restriction on gas-exchange of four papaya genotypes 93 CAMPOSTRINI,ELIEMAR; YAMANISHI,OSVALDO KIYOSHI. Four papaya genotypes, two from the ‘Solo’ group (Sunrise Solo TJ and Improved Sunrise Solo line 72/12) and two from the ‘Formosa’ group (Tainung 02 and Know You 01) grown in ultisol under field conditions in Macaé, RJ, Brazil, were used in this study. Two different effective depths (ED) were determined in the area using a penetrographer with average soil moisture of 11.2%. The area with ED of 0.35 m with a maximum pressure of 4.12 MPa for penetration was defined as an area with restriction (WR) to root growth, while, the area with minimum ED of 0.60 m and a pressure lower than 2.30 MPa as an area with no restriction (NR). The net CO2 assimilation rate (A), stomatal conductance (g s), leaf temperature (Tl), intercellular partial pressure of CO2 (c i) and... Tipo: Info:eu-repo/semantics/article Palavras-chave: Carica papaya L.; Photosynthesis; Leaf temperature; Stomatal conductance; Intrinsic water use efficiency. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000200002 Efeito do estresse salino e da prolina exógena em calos de milho 93 CAMARA,TEREZINHA RANGEL; WILLADINO,LILIA; TORNÉ,JOSEP MARIA; MANICK,ALBERT; SANTOS,MARIA ASUNCIÓN. O presente trabalho teve por objetivo avaliar o efeito de diferentes concentrações de NaCl (0, 68, 137 e 205 mM) sobre o cultivo in vitro de calos de dois genótipos (W64Ao2 e Arizona 8601) de milho (Zea mays L.), em meio de cultura N6, suplementado ou não com a adição de 6,0 mM de prolina. Os tratamentos consistiram da combinação dos quatro níveis de NaCl com os dois níveis de prolina, num fatorial 4x2. Os tratamentos foram mantidos durante 60 dias, com subcultivos a cada 20 dias. A taxa de crescimento dos calos e o conteúdo endógeno de putrescina, espermina, espermidina, prolina e outros aminoácidos livres foram avaliados no final do período experimental. A adição de prolina exógena favoreceu o crescimento dos calos no tratamento-controle e minorou os... Tipo: Info:eu-repo/semantics/article Palavras-chave: Aminoácidos; Poliaminas; Salinidade; Zea mays. Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312000000200005 New proposal of classification of seeds based on forms of phytochrome instead of photoblastism 93 TAKAKI,MASSANORI. The paper proposes the classification of seeds in relation to the forms of phytochrome instead of classical photoblastism. On the basis of published data all seeds have phytochrome and the term photoblastism should be replaced by forms of phytochrome that control germination: 1. Positive photoblastic seeds have phyB (and, to a lesser extent, phyD and phyE) controlling the germination process through Low Fluence Responses (LFR); 2. Negative photoblastic seeds have phyA controlling germination through High Irradiance Responses (HIR) and, when the pre-existing Pfr level is high enough to induce germination in darkness, through LFR by phyB; and 3. light insensitive seeds have phyA controlling germination through Very Low Fluence Responses (VLFR). Tipo: Info:eu-repo/semantics/article Palavras-chave: Seed classification; Photoblastism; Phytochrome forms; Mode of action. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000100011 Effects of preculture with sucrose and aba on cell suspensions water status and its relation with vitrification resistance 93 SEIJO,GUILLERMO. Changes in cell water relations during precultures were followed in an attempt to understand the mechanism of cell hardening for cryopreservation by vitrification. Medium containing 0.4 M sucrose (psiw=-1.45 MPa) and containing 5 mg L-1 of ABA (MT psiw=-0.73 MPa and MS psiw=-0.48 MPa) were used to harden cell suspensions of orange and carrot. Preculture in these medium did not cause a significant decrease of cell viability, however, it improved the cell survival to PVS2 and liquid nitrogen expositions. When cells were inoculated into medium containing 0.4 M sucrose, the cell psiw decreased rapidly until reach the medium psiw , and turgor was also severely reduced or disappeared. Subsequently, cell psis began to decrease and after 48 h of treatment in low... Tipo: Info:eu-repo/semantics/article Palavras-chave: Preculture; Cell suspension; Sucrose; ABA; Cryopreservation. Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312000000200007 Glutamine synthetase and glutamate synthase activities in relation to nitrogen fixation in Lotus spp. 93 GONNET,SUSANA; DÍAZ,PEDRO. Lotus corniculatus, L. tenuis, L. pedunculatus, and L. subbiflorus inoculated with Mesorhizobium loti NZP2037 strain were grown in a growth chamber. The plants dry weight (DW), the nodule fresh weight (FW), the nitrogenase activity, the nodule glutamine synthetase (GS) and glutamate synthase (GOGAT) activities, as well as the leghemoglobin content and the amino acid in the stem were measured 28 days after inoculation. The highest DW of plants was measured in L. tenuis and the highest FW of nodules was measured in L. pedunculatus. Nitrogenase activity in L. tenuis, L. pedunculatus and L. subbiflorus was six fold the activity in L. corniculatus. Nodule GS and GOGAT activities did not follow this same pattern. L. tenuis had the highest values of GS and GOGAT... Tipo: Info:eu-repo/semantics/article Palavras-chave: Nitrogen fixation; Nitrogenase; Mesorhizobium loti; Leghemoglobin; Ammonia assimilation. Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312000000300003 Regulation of in vitro somatic embryogenesis with emphasis on to the role of endogenous hormones 93 JIMÉNEZ,VÍCTOR M.. Different aspects of the in vitro somatic embryogenesis regulation are reviewed in this paper.work. A description of g General aspects, such as terminology, uses, stages of development and factors associated with the somatic embryogenesis, are described. is carried out. Although a brief description ofn the effects of the addition of different plant growth regulators to the culture medium wasis given, the article is centereds itself on the effect that the endogenous hormone concentrations in the initial explants and in the tissue cultures derived from them could play oin the induction and expression of somatic embryogenesis. It is significant that few to emphasize the low amount of systematic studies have been conducted, in this subject, in which different... Tipo: Info:eu-repo/semantics/article Palavras-chave: In vitro morphogenesis; Embryo regeneration; Embryogenic competence; Plant growth regulators; Hormones. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000200008 Fluxo de seiva e condutância estomática de duas espécies lenhosas sempre-verdes no campo sujo e cerradão 93 NAVES-BARBIERO,CHEILA CRISTINA; FRANCO,AUGUSTO CÉSAR; BUCCI,SANDRA JANET; GOLDSTEIN,GUILHERMO. No presente estudo, comparou-se o curso diário de fluxo de seiva, condutância estomática e potencial hídrico (psi) de duas espécies sempre-verdes, Rapanea guianensis e Roupala montana. Os dados foram obtidos no final da estação seca, quando os efeitos do déficit hídrico seriam mais acentuados. As medidas foram realizadas no campo sujo, onde predomina gramíneas com sistemas radiculares superficiais, e no cerradão, em que a maior densidade de elementos lenhosos com sistemas radiculares profundos poderia levar a um esgotamento das reservas de água do subsolo na estação seca. Valores máximos de psinão diferiram para as duas espécies nas duas fisionomias estudadas. Os valores mínimos de potencial hídrico foliar de R. guianensis foram mais negativos (P<0,05)... Tipo: Info:eu-repo/semantics/article Palavras-chave: Rapanea guianensis; Roupala montana; Transpiração; Cerrado; Potencial hídrico. Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312000000200003 Absorção e acúmulo de cádmio e seus efeitos sobre o crescimento relativo de plantas de aguapé e de salvínia 93 OLIVEIRA,JURACI ALVES DE; CAMBRAIA,JOSÉ; CANO,MARCO ANTONIO OLIVA; JORDÃO,CLÁUDIO PEREIRA. A absorção e acúmulo de Cd e seus efeitos sobre o crescimento relativo foram estudados em aguapé (Eichhornia crassipes (Mart.) Solms) e salvínia (Salvinia auriculata Aubl.), em solução nutritiva. O aguapé absorveu quantidade significativamente maior de Cd do que a salvínia, tendo a diferença aumentado com o tempo de exposição ao Cd. O Km da absorção de Cd, estatisticamente igual nas duas espécies aquáticas quando as folhas contatavam a solução nutritiva, tornou-se maior em salvínia quando se impediu fisicamente que as folhas contatassem a solução de absorção. O Vmax de absorção de Cd, por outro lado, foi sempre maior em salvínia, independentemente do contato ou não das folhas com a solução nutritiva. A quantidade de Cd adsorvido e absorvido aumentou com a... Tipo: Info:eu-repo/semantics/article Palavras-chave: Metais pesados; Tolerância a cádmio; Plantas aquáticas. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000300008 Temperature-dependent germination and endo-beta -mannanase activity in sesame seeds 93 CARVALHO,PATRÍCIA GONÇALVES BAPTISTA DE; BORGHETTI,FABIAN; BUCKERIDGE,MARCOS SILVEIRA; MORHY,LAURO; FERREIRA FILHO,EDIVALDO XIMENES. The effects of temperature on germination and endo-beta-mannanase activity in seeds of Sesamum indicum was investigated. The minimum germination temperature (Tmin) lies between 12.8°C and 13.2°C while the maximum temperature (Tmax) is located between 45.5°C and 46°C. Germinabilities are statistically not different from estimated viability (88%) between 18.8°C and 43.2°C. The Mann-Whitney test indicated the interval 31.9°C to 35.1°C as the optimum temperature (Topt) range for germination rate. When seeds incubated at temperatures at or below the Tmin and close to or above the Tmax were transferred to 30°C, those incubated at lower temperatures achieved high germinability. On the other hand, the higher the pre-incubation temperature above Tmax, the lower the... Tipo: Info:eu-repo/semantics/article Palavras-chave: Endosperm; Germination rate; Sesame. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000200003 Nitrate reductase and glutamine synthetase activities in S1 endogamic families of the maize populations Sol da Manhã NF and Catetão 93 MACHADO,ALTAIR TOLEDO; SODEK,LADASLAV; PATERNIANI,ERNESTO; FERNANDES,MÂNLIO SILVESTRE. The possibility of improving nitrogen use efficiency in maize was investigated using S1 endogamic families of the populations Sol da Manhã NF and Catetão. A simple 10 X 10 lattice design was adopted and the trials carried out at the experimental field of MITLA AGRÍCOLA LTDA, in Uberlândia, State of Minas Gerais, during the 1994/95 planting season. Based on grain production figures, the three best and three worst performing S1 endogamic families were selected for this study. These were pooled to form four sub-populations denominated NFB, NFR (the best and worst families, respectively, of the Sol da Manhã NF variety), CATB and CATR (the best and worst families, respectively, of the Catetão variety). Each of these sub-populations was evaluated under... Tipo: Info:eu-repo/semantics/article Palavras-chave: Corn; Nitrogen efficiency; Nitrogen forms; Nitrogen uptake. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000100010 Soybean seed galactinol synthase activity as determined by a novel colorimetric assay 93 RIBEIRO,MARLUCI; FELIX,CARLOS R.; LOZZI,SILENE DE PAULINO. Galactinol synthase (GS) is a key enzyme for the biosynthesis of raffinose oligosaccharides (RO) which are the flatulence factors present in soybean seeds and several other legumes. Understanding of soybean seed GS properties is, therefore, of biotechnological interest. The GS enzyme catalyses formation of galactinol and UDP from UDP-gal and myo-inositol. This enzyme is currently assayed by an isotopic method. We have then idealized a more convenient method for GS assay based on the indirect colorimetric determination of the UDP formed which is then hydrolyzed by exogenous apyrase and the resulting Pi quantified by a modification of the colorimetric method of Fiske &amp; SubbaRow. The color developed is stable, and the method is suitable for detection... Tipo: Info:eu-repo/semantics/article Palavras-chave: Flatulence; Galactinol synthase; Colorimetric assay; Raffinose oligosaccharides. Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312000000300004 Lectins from Pisum arvense seeds behave differently from storage proteins during germination in the darkness 93 SILVA,LUIZA IZABEL M. MOREIRA DA; RAMOS,MÁRCIO VIANA; CAJAZEIRAS,JOÃO BATISTA; FERREIRA,PATRÍCIA RODRIGUES; CARVALHO,CARLOS ALBERTO V.; GRANGEIRO,THALLES BARBOSA; NUNES,EDSON PAULA; SAMPAIO,ALEXANDRE HOLANDA; FREITAS,BEATRIZ TUPINAMBÁ; SILVEIRA,JOAQUIM ALBENÍSIO G. DA; CAVADA,BENILDO SOUSA. ABSTRACT - The mobilization of seed proteins from Pisum arvense L. during germination in the absence of light was studied. The seeds were found to be completely consumed 22 days after germination and seedlings ceased growth after the 18th day. SDS-PAGE indicated that the main protein bands correspond to high molecular mass storage proteins which undergo proteolysis in the initial stages of germination and are not detected after the 7th day of germination. However, the corresponding lectin profiles were detected during the entire germination process, suggesting that these proteins are strongly resistant to seed proteolytic enzymes and should be important for seedling establishment. Furthermore, haemagglutinating activity in cotyledons was detected until 22... Tipo: Info:eu-repo/semantics/article Palavras-chave: Lectin; Protein mobilization; Seed germination. Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312000000300008 Acúmulo e distribuição de metais pesados nas raízes, caule e folhas de mudas de árvores em solo contaminado por rejeitos de indústria de zinco 93 SOARES,CLÁUDIO ROBERTO FONSÊCA SOUSA; ACCIOLY,ADRIANA MARIA DE AGUIAR; MARQUES,TERESA CRISTINA LARA LANZA DE SÁ E MELO; SIQUEIRA,JOSÉ OSWALDO; MOREIRA,FÁTIMA MARIA SOUZA. Avaliaram-se em casa-de-vegetação o acúmulo e a distribuição de metais pesados nas raízes, caule e folhas de mudas de vinte espécies arbóreas tropicais crescendo em solo contaminado com metais pesados. As mudas com tamanho ideal para plantio foram transferidas para vasos contendo 3,3 kg de solo sem contaminação ou contaminado com Zn, Cd, Cu e Pb, onde permaneceram por 90 dias. As espécies que cresceram em solo contaminado apresentaram teores foliares elevados, variando de (mg kg-1): Zn = 154 a 1177; Cd = 0,6 a 54,6; e Cu = 2,8 a 134. Essas concentrações foram, em muitos casos, superiores aos níveis críticos de toxidez, ao passo que os teores foliares de Pb variaram de 0,1 a 4,3 mg kg-1, não atingindo níveis considerados fitotóxicos. Em algumas espécies... Tipo: Info:eu-repo/semantics/article Palavras-chave: Toxicidade de metais pesados; Níveis críticos; Poluição do solo; Mudas de árvores tropicais. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000300006 Partial purification and characterization of ribonucleases from roots, stem and leaves of cowpea 93 FRANCO,OCTÁVIO LUIZ; GONDIM,LORRANCE ABREU; BEZERRA,KÁTIA REGINA; GUERRA,MARIA ELANE DE CARVALHO; LIMA,CARMEM ROGÉLIA FARIAS MACHADO; ENÉAS-FILHO,JOAQUIM; PRISCO,JOSÉ TARQUÍNIO; GOMES-FILHO,ENÉAS. Partial purification and characterization of ribonucleases (RNase; EC 3.1.27.1) present in roots, stem and leaves of 5 day-old Pitiúba cowpea [Vigna unguiculata (L.) Walp.] seedlings are described. Crude extracts from the different tissues were precipitated with ammonium sulfate followed by ionic exchange chromatography (CM-Cellulose) resulting in purification factors of 48-fold for roots, 21 for stem and 42 for leaves. No deoxyribonuclease activity was practically observed. The molecular masses of the RNases did not significantly differ, averaging 16.3 kDa. Leaf RNase was stable up to 50ºC while the others were inactivated at this temperature. The maximal inactivation for both stem and roots RNases was reached at 70ºC while for leaf it occurred at 80ºC.... Tipo: Info:eu-repo/semantics/article Palavras-chave: Enzyme effectors; Molecular mass; Nuclease; Optimum pH; Seedlings; Thermostability; Vigna unguiculata. Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-31312001000300010 Registros recuperados: 48 Primeira ... 1 2 3 ... Última

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