oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Longitudinal and radial variation of extractives and total lignin contents in a clone of Eucalyptus grandis W.Hill ex Maiden x Eucalyptus urophylla S. T. Blake  [PDF]
Marina Donária Chaves Arantes,Paulo Fernando Trugilho,José Tarcísio Lima,Angélica de Cássia Oliveira Carneiro
CERNE , 2011,
Abstract: The objective of this work was to determine concentrations of extractives and total lignin along with their radial and longitudinal variations in wood from a clone of Eucalyptus grandis W.Hill ex Maiden x Eucalyptus urophylla S. T. Blake at age six years. Longitudinal samples were taken at 2%, 10%, 30% and 70% of the commercial height of trees, and radial samples were taken from each longitudinal position, the number of samples depending on the diameter of each disk. Results led to the conclusion that, overall, concentrations of extractives and total lignin in the wood tended to decrease with increasing distance from the pith and tended to increase in portions closer to the tree base.
DEFICIENCY SYMPTOMS OF MACRONUTRIENTS AND OF BORON IN HYBRIDS CLONES OF Eucalyptus grandis WITH Eucalyptus urophylla
Ronaldo Luiz Vaz de Arruda Silveira,Ad?nis Moreira,Ernesto Norio Takashi,Fábio Sgarbi
CERNE , 2002,
Abstract: ABSTRACT: To characterise symptoms of macronutrient and boron deficiencies in hybrid clones ofEucalyptus grandis with Eucalyptus urophylla, a trial was conducted using nutrient solution, withtreatments including complete solution and minus N, minus P, minus K, minus Ca, minus Mg, minus Sand minus B with four replicates. Descriptions of the symptoms were made monthly, 4 months afterthe establishment of the treatments. Samples of leaves were collected to determine nutrient concentrations,taking the fifth and sixth leaf as standards, counted from the tip of the branches in both upperand lower parts of the crown. Another sampling was performed, collecting only leaves with deficiencysymptoms,for N, P, K and Mg using old leaves and for Ca, S and B young leaves. The sequence of symptomsappearance was N, P, B, K, Ca, Mg and S. Nutrients concentrations in leaves of treatments withomitted nutrients were lower as compared to leaves of the complete treatment, indicating that thesymptoms described were really due to the deficiency effect. The nutrient concentration of leaves withhigh symptoms was smaller than those for the fifth and sixth leaves, except for calcium. Eventhough,these leaves appeared to be adequate to predict nutritional deficiencies in Eucalyptus. The highestintensity of symptoms occurred for boron and the lowest for sulphur.
Estimativa da biomassa e do comprimento de raízes finas em Eucalyptus urophylla S.T. Blake no município de Santa Maria-RS
Witschoreck, Rudi;Schumacher, Mauro Valdir;Caldeira, Marcos Vinicius Winckler;
Revista árvore , 2003, DOI: 10.1590/S0100-67622003000200008
Abstract: this study aimed to estimate the amount of biomass and the length of fine roots (< 2mm of diameter) in different soil depths for the 10 -year-old species eucalyptus urophylla s.t. blake. the experiment was conducted santa maria, rs on the campus of the federal university of santa maria. the plots were 27 m long and 14 m wide and 3 m x 2 spaced. four monoliths of 25 cm x 25 cm x 60 cm were sampled and divided into six geometric sections at depths of 0-10, 10-20, 20-30, 30-40, 40-50, 50-60 cm. roots were separated from the soil by using a set of two sieves (2 mm and 1 mm) and water jets. the intersection method was used to determine root length producing photos with the use of a scanner. the results showed a high concentration of fine roots in the first 20 cm of the soil. fine root total biomass found for eucalyptus urophylla was 1.451,6 kg/ha, 57.9% were concentrated in the first 20 cm of soil. the total length of fine roots was 27.968,9 km/ha, with 64.3% being in the first 20 cm of depth.
Efficiency of phosphorus use in young plants of Eucalyptus urophylla S. T. Blake  [PDF]
Thais Galhardo Godoy,Sebasti?o Carlos da Silva Rosado
CERNE , 2011,
Abstract: The objective of this study is to select superior genotypes for efficiency of phosphorus use in seedlings of Eucalyptus urophylla, correlating them with initial height growth in the field, at age eight months. A completely randomized block design was used in the nursery, consisting of eight clones, three replicates and four plants per plot. The same design was used in the field, consisting of eight clones, four replicate blocks and nine plants per plot. Data being collected in the nursery at age 120 days included: phosphorus concentration in shoot (CPPA); phosphorus concentration in root (CPR); phosphorus content in shoot (CtPPA); phosphorus content in root (CtPR); total phosphorus content in seedling (CtPT); phosphorus use efficiency in shoot (EUP-PA); phosphorus use efficiency in root (EUP-R) and total phosphorus use efficiency (EUP-T). Analyses of variance showed significant genetic differences among clones for all traits and, given the high heritability values found, estimated genetic gains were generically very high. As regards predicted indirect genetic gain, it was noted that selection on nursery seedlings for all EUPs provided the highest values of indirect gain in height of field seedlings.
Organogênese in vitro a partir de explante caulinar na regenera??o de clones de Eucalyptus grandis W. Hill ex Maiden X E. urophylla S. T. Blake
Alves, Elisa Cristina Soares de Carvalho;Xavier, Aloisio;Otoni, Wagner Campos;
Revista árvore , 2004, DOI: 10.1590/S0100-67622004000500003
Abstract: with the objective of testing in vitro regeneration through organogenesis from stem explants of three hybrid clones of eucalyptus grandis x eucalyptus urophylla, the effects of the growth regulators tdz [1-phenil-3-(1, 2, 3-thiadiazol-5-il)urea], bap (6-benzilaminopurine) and naa (naphthalene acetic acid) were evaluated. in general, a differentiated clone response in relation to intensity, texture, color and oxidation degree of calli was observed due to growth regulator treatments. the best results in callus formation were recorded for the treatments with the combination tdz (0,5 mg l-1) and ana (0,1 mg l-1), achieving 100% of callus formation from the stem explants. compact node structures appeared mainly in the extremities of the stem explants, being those areas responsible for the regeneration of adventitious buds. the best regeneration response was obtained with 1,0 mg l-1 bap.
Efeito da incorpora??o de casca de café nas propriedades físico-mecanicas de painéis aglomerados de Eucalyptus urophylla S.T. Blake
Mendes, Rafael Farinassi;Mendes, Lourival Marin;Guimar?es Júnior, José Benedito;Mori, Fábio Akira;César, Antonia Amanda da Silva;
Ciência e Agrotecnologia , 2010, DOI: 10.1590/S1413-70542010000300012
Abstract: the objective of this study was to evaluate the influence of the incorporation of coffee husks in the production of particleboard with eucalyptus urophylla s.t. blake. the panels were produced incorporating 25%, 50%, and 75% of coffee husks at three levels of resin phenol-formaldehyde (6, 9 and 12%) and 1% of paraffin. the nominal density of the panels was 0.7 g/cm3 and the cycle of pressing consisted in a pressure of 3.92 mpa under a temperature of 180°c for 8 minutes. by the results it was possible to observe that the physical properties of the particleboard have a linear relationship decreasing with the increase in the level of resin, and increasing with the increase in the percentage of coffee husks, showing higher values of water absorption and thickness swelling. the mechanical properties show a linear relationship growing with the increase of resin level, and decreasing with a reduction the percentage of coffee husk association. the way that the search was conducted, the incorporation of the coffee husks harms the quality of the panels produced.
Estimativa da biomassa e do comprimento de raízes finas em Eucalyptus urophylla S.T. Blake no município de Santa Maria-RS
Witschoreck Rudi,Schumacher Mauro Valdir,Caldeira Marcos Vinicius Winckler
Revista árvore , 2003,
Abstract: O objetivo do presente trabalho foi estimar a biomassa e o comprimento de raízes finas (< 2 mm de diametro), em diferentes profundidades do solo, para a espécieEucalyptus urophylla S.T. Blake, com 10 anos de idade. O estudo foi realizado no município de Santa Maria-RS, no campus da Universidade Federal de Santa Maria. O talh o plantado com eucalipto tem 27 m de comprimento por 14 m de largura, em espa amento 3 x 2 m. Foram amostrados quatro monolitos de 25 x 25 x 60 cm. Os monolitos foram divididos em seis perfis geométricos, nas profundidades de 0-10, 10-20, 20-30, 30-40, 40-50, 50-60 cm. A separa o das raízes do solo foi por meio de um conjunto de duas peneiras (2 e 1 mm de malha) e jatos d'água. Na determina o do comprimento de raízes foi utilizado o método de intersec o, produzindo fotos com o uso de scanner. Os resultados revelaram alta concentra o das raízes finas nos primeiros 20 cm de solo. A biomassa total de raízes finas encontradas para o Eucalyptus urophylla foi de 1.451,6 kg/ha, devendo ser ressaltado que 57,9% estavam concentradas nos primeiros 20 cm de solo. Constatou-se que o comprimento total de raízes finas foi de 27.968,9 km/ha e que 64,3% destes estavam nos primeiros 20 cm de profundidade.
RADIAL VARIATION OF MICROFIBRIL ANGLE AND WOOD DENSITY AND THEIR RELATIONSHIPS IN 14-YEAR-OLD Eucalyptus urophylla S.T. BLAKE WOOD  [PDF]
Paulo Ricardo Gherardi Hein,Lo?c Brancheriau Mail
BioResources , 2011,
Abstract: The orientation of cellulose microfibrils in the cell wall along the stem axis has major effects on stiffness and longitudinal shrinkage and is of key importance in wood quality. The aim of this study was to investigate the radial variability of MFA and wood density (ρ) and their relationships in Eucalyptus urophylla wood. Three MFA values were estimated by X-ray diffraction at three points of each one of the 175 tangential sections, and the basic density was measured. A decrease of microfibril angles from pith to bark can be observed in most samples; however, some radial strips presented different patterns of variation. For basic density, a linear significant increase from pith to bark was confirmed. There was no significant correlation between microfibril angle and density. The relationships among the three MFA estimated on tangential sections of wood were strong. The “curvature effect” due to the growth rings had a negligible effect on the three measurements of tangential sections cut near to the pith. This study showed that a single T value measurement by X-ray diffraction, preferably at the centre of the tangential section, is precisely sufficient to estimate the mean MFA of Eucalyptus urophylla wood.
Teor de Lignina em Plantas de Eucalyptus urophylla S. T. Blake Tratadas com Fitorreguladores
Oliveira,Maria Beatriz de; Abreu,Heber dos Santos; Pereira,Regina Paula Willemen;
Silva Lusitana , 2009,
Abstract: lignin is an indispensable biomacromolecule for various biological processes in plants. one of the most important lignin functions is to maintain the rigidity needed for the verticality of the main stem and to ensure the water and mineral movement. this research was carried out with seedlings of eucalyptus urophylla and the results may facilitate further studies in biotechnology. in this research were applied different concentrations of plant growth regulators jasmonic acid (1 and 2 μm) and 2,4-dichlorophenoxyacetic acid (18.12 and 36.24 μm)]. the experiment was full factorial with a completely randomized design. the results showed that the treatment with jasmonic acid in its first dosage enabled the process of lignin formation and in a second dosage disabled the process of lignification. in the treatment with 2,4-d (a1-18.12 μ m) the process of lignification contributed to reduce the deposition of lignin, while (a2 - 36.24 μm) had a smaller reduction compared with the standard. the combined treatments j1a1 (1 μm jasmonic acid and 18.12 + μ m 2,4-d) and j1a2 (2 μ m jasmonic acid and (36.24 + μ m 2,4-d) showed synergistic effect with a predominance of jasmonic acid on lignin formation. the results pointed out for change in the lignification process as well as protein and anatomical features.
Avalia??o da madeira de Eucalyptus camaldulensis Dehnh e Eucalyptus urophylla S.T. Blake em ensaios de usinagem, visando à produ??o moveleira
Souza, Maria Odete Alves de;Silva, José de Castro;Lucia, Ricardo Marius Della;Evangelista, Wescley Viana;
Revista árvore , 2009, DOI: 10.1590/S0100-67622009000400018
Abstract: the objective of this research was to conduct machining tests in woods of 6 and 8-year-old eucalyptus urophylla and of a ten-year old eucalyptus camaldulensis and to evaluate their possible use by the furniture industry. the wood samples were obtained from six trees of each clone, planted in a consortium with cattle and grain, owned by votorantim metals and zinc. the plantation is located in the neighborhood of the city of vazante, in the state of minas gerais. the following essays were conducted: cut by a table saw either parallel or perpendicular to the grain; shaping; planing; drilling; routing; mortising and drilling for dowels. all the samples yielded satisfactory results, mainly the eight year old eucalyptus urophylla, during parallel-to-the-grain and mortising sawing. woods from the clones tested seem very appropriate for furniture production. in fact, the samples did not show any difficulties during machining.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.