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Strain-Hardening Cement-Based Composites (SHCCs) exhibit high toughness and durability, allowing the design of resilient structures. Despite the exceptional properties of SHCC and the current modeling techniques, the widespread use of the composite is limited. One limiting factor is developing and validating analytical models that could be used for optimizing mixes and designing structural elements. Furthermore, the composite mechanical response is complex and depends on several phenomena, such as fiber pullout, fiber orientation and distribution, size effect, fiber content, group effect, embedding length, fiber dimensions, and matrix strength. In this context, this research presents the state-of-the-art on the micro- and mesomechanisms occurring in SHCC during cracking and robust techniques to predict its tensile behavior accounting for such phenomena already proved experimentally. The study is relevant for designers and the scientific community because it presents the gaps for the research groups to develop new investigations for consolidating SHCC, which is a material to produce resilient structures.

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Backup rolls are the main tool in a four-high rolling mill; the rolling forces applied in load cells promote the fatigue of the material due to mechanical contact between backup rolls and work rolls. This work investigated the causes of recurrent failures in backup rolls, with cracking always initiated on the surface of the roll body and finishing in the main radius between neck and roll body. Aiming to find the causes of failure, visual inspection and morphology of the fracture were performed, complemented with mechanical tests of hardness on the stress concentration area, in addition to validating the results by applying the finite element method, using ANSYS Mechanical Static Structural Software. It was concluded that the fatigue crack initiated on the surface of BUR due to work hardening continued growing up over the fatigued material, creating beach marks, and finally, a fracture occurred in the main radius of BUR due to stress concentration. The work hardening is the main cause of spalling on BURs and other mechanical components exposed to mechanical contact.

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Two phases are generally recognized in the enzymatic coagulation of milk: hydrolysis and aggregation, although nowadays more and more researchers consider the non-enzymatic phase to actually be a stage of gel formation made up of two sub-stages: micellar aggregation and hardening of the three-dimensional network of para-κ-casein. To evaluate this controversy, the main descriptive models have been reviewed. Most of them can only model micellar aggregation, without modeling the hardening stage. Some are not generalizable enough. However, more recent models have been proposed, applicable to a wide range of conditions, which could differentiate both substages. Manufacturing quality enzymatic cheeses in a cost-effective and consistent manner requires effective control of coagulation, which implies studying the non-enzymatic sub-stages of coagulation separately, as numerous studies require specific measurement methods for each of them. Some authors have recently reviewed the micellar aggregation models, but without differentiating it from hardening. Therefore, a review of the proposed models is necessary, as coagulation cannot be controlled without knowing its mechanisms and the stages that constitute it.

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Increasingly stringent environmental regulations in different sectors of industry, especially the aeronautical sector, suggest the need for more investigations regarding the effect of environmentally friendly corrosion protective processes. Passivation is a finishing process that makes stainless steels more rust resistant, removing free iron from the steel surface resulting from machining operations. This results in the formation of a protective oxide layer that is less likely to react with the environment and cause corrosion. The most commonly used passivating agent is nitric acid. However, it is know that high levels of toxicity can be generated by using this agent. In this work, a study has been carried out into the electrochemical behavior of 15-5PH (precipitation hardening) and 17-4PH stainless steels passivated with (a) citric and (b) nitric acid solutions for 60 and 90 min at 49 °C, and subsequently exposed to an environment with chlorides. Two electrochemical techniques were used: electrochemical noise (EN) and potentiodynamic polarization curves (PPC) according to ASTM G199-09 and ASTM G5-13, respectively. The results obtained indicated that, for both types of steel, the passive layer formed in citric acid as passivating solution had very similar characteristics to that formed with nitric acid. Furthermore, after exposure to the chloride-containing solution and according with the localization index (LI) values obtained, the stainless steels passivated in citric acid showed a mixed type of corrosion, whereas the steels passivated in nitric acid showed localized corrosion. Overall, the results of the R n values derived show very low and similar corrosion rates for the stainless steels passivated with both citric and nitric acid solutions.

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O objetivo deste estudo foi analisar a influência do tamanho campo de visão ou FOV (field of view) e o posicionamento na arcada de estruturas densas na formação de artefatos em exames de tomografia computadorizada de feixe cônico(TCFC). Foram utilizadas raízes de dentes bovinos em um simulador de mandíbula em acrílico simulando a posição dos dentes. A obtenção das imagens ocorreu por meio dos tomógrafos Kodak 9000 com FOV pequeno e o Kodak 9500 com FOVs médio e grande. Para aquisição das imagens, o simulador foi posicionado sempre de forma padronizada. O grupo controle foi estabelecido a partir do escaneamento de seis raízes de dentes bovinos hígidas. Cada uma das seis raízes foi substituída por um implante ou raiz bovina preenchida com guta-percha (materiais hiperdensos) e uma nova imagem tomográfica foi realizada em cada tomógrafo para cada modificação. Todas as imagens foram avaliadas no software Image J para avaliação dos valores de cinza na região cervical, média e apical de cada raiz e comparadas com a imagem do grupo controle. Foi verificado que a interação entre tamanho do FOV, material e região não foi significativa (p=0,983). A interação entre material e região, não tiveram diferenças significativas (p=0,904). Para a relação entre tamanho do FOV e material evidenciou-se a presença de diferença significativa (p<0,001). Observou-se que os valores no FOV médio e pequeno apresentaram p<0,001, quando confrontado com o grupo controle. Concluiu-se que os valores de cinza não se diferem conforme localização do material hiperdenso dentro da arcada e que o FOV pequeno é o que apresenta menor média quando se compara material e região. (AU)

The objective of this study was to analyze the influence of the field of view or FOV (field of view) size and the positioning in the arch of dense structures in the formation of artifacts in cone beam computed tomography (TCFC) exams. Bovine tooth roots were used in an acrylic jaw simulator simulating the position of the teeth. The images were obtained using Kodak 9000 tomographs with small FOV and Kodak 9500 with medium and large FOVs. For image acquisition, the simulator was always positioned in a standardized way. The gold standard was established by scanning six roots of healthy bovine teeth. Each of the six roots was replaced by an implant or bovine root filled with gutta-percha (hyperdense materials) and a new tomographic image was performed on each tomography for each modification. All images were evaluated using the Image J software to assess the gray values in the cervical, middle and apical regions of each root and compared with the gold standard image. It was found that the interaction between FOV size, material and region was not significant (p = 0.983). The interaction between material and region, did not have significant differences (p = 0.904). For the relationship between FOV size and material, the presence of a significant difference was evidenced (p <0.001). It was observed that the values in the medium and small FOV presented p <0.001, when compared with the gold standard. It was concluded that the gray values do not differ according to the location of the hyperdense material within the arch and that the small FOV is the one with the lowest average when comparing material and region. (AU)

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Precipitation hardening aluminum alloys are used in many industries due to their excellent mechanical properties, including good weldability. During a welding process, the tensile strength of the joint is critical to appropriately exploit the original properties of the material. The welding processes are still under study, and gas metal arc welding (GMAW) in pulsed metal-transfer configuration is one of the best choices to join these alloys. In this study, the welding of 6061 aluminum alloy by pulsed GMAW was performed under two heat treatment conditions and by using two filler metals, namely: ER 4043 (AlSi5) and ER 4553 (AlMg5Cr). A solubilization heat treatment T4 was used to dissolve the precipitates of ß"- phase into the aluminum matrix from the original T6 heat treatment, leading in the formation of ß-phase precipitates instead, which contributes to higher mechanical resistance. As a result, the T4 heat treatment improves the quality of the weld joint and increases the tensile strength in comparison to the T6 condition. The filler metal also plays an important role, and our results indicate that the use of ER 4043 produces stronger joints than ER 4553, but only under specific processing conditions, which include a moderate heat net flux. The latter is explained because Mg, Si and Cu are reported as precursors of the production of ß"- phase due to heat input from the welding process and the redistribution of both: ß" and ß precipitates, causes a ductile intergranular fracture near the heat affected zone of the weld joint.

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The present study was undertaken to examine the antidiabetic potential of naturally occurring peptides and hydrolysate fractions from easy-to-cook (ETC) and hard-to-cook (HTC) beans. All fractions were tested regarding their in vitro inhibitory activities against α-amylase and α-glucosidase as well as in vivo anti-hyperglycemic and hypoglycemic effects. Results evidenced that the peptide fractions with the lowest molecular weight (<3 kDa) have the highest inhibitory activities, and a 16.9%-89.1% inhibition of α-amylase and 34.4%-89.2% inhibition of α-glucosidase were observed. Regarding the antihyperglycemic activity, the fraction ETCNO3-10 showed a better performance than the positive control (acarbose). In addition, results from hypoglycemic activity evidenced that the tested peptide fractions were able to decrease the glucose levels at the same extension of glibenclamide, maintaining a constant basal glucose level without a postprandial hyperglycemia peak. Finally, it is possible to suggest that the naturally occurring peptides and hydrolysate fractions obtained from ETC and HTC common beans could be used in functional food production or pharmaceutical formulations to prevent diabetes.

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Reproduction is strongly influenced by environmental temperature in insects. At high temperature, mating success could be influenced not only by basal (non-inducible) thermotolerance but also by inducible plastic responses. Here, mating success at high temperature was tested in flies carrying contrasting genotypes of heat resistance in Drosophila melanogaster. The possible heat-hardening effect was tested. Mating success did not differ between heat-resistant and heat-sensitive genotypes when tested both at high (33 °C) and benign (25 °C) temperature, independently of the heat-hardening status. Importantly, heat-hardening pre-treatment increased in a 70% the number of matings at 33 °C in a mass-mating experiment. Further, mating latency at 33 °C was shorter with heat hardening than without it in single-pair assays Heat-hardening had previously been showed to improve short-term thermotolerance in many organisms including Drosophila, and the present results show that heat hardening also improve mating success at elevated temperature. Previous exposures to a mild heat stress improve short-term mating success as a plastic response of ecological relevance. Such heat-hardening effects on mating success should be relevant for predicting potential evolutionary responses to any possible current scenery of global warming, as well as in sterile insect release programs for pest control in elevated temperature environments.

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Objetivo: o objetivo desta pesquisa foi avaliar o tempo e o fluxo de endurecimento do cimento AH-PLUS e MTA nas proporções de 10%, 20% e 30%, a fim de adicionar a capacidade de estimular a deposição de tecido duro. Material e Métodos: Para o teste de fluxo, 0,5 ml de cimento foram depositados em uma placa de vidro e outra placa foi adicionada com uma carga adicional, após 10 minutos a carga foi removida e o diâmetro do círculo formado pelo cimento foi medido com um Bússola digital. Para o tempo de endurecimento, foram utilizados moldes cilíndricos preenchidos com o cimento testado, mantidos dentro de um forno e os testes de agulha de Gillmore foram realizados no material em intervalos de 60 segundos até que as marcas não fossem visíveis na superfície do cimento testado. Resultados: Na vazão, os valores obtidos foram: 41,1 mm (10% MTA), 32,86 mm (20% MTA), 21,91 mm (30% MTA), 24,41 mm AHPlus® e 26,47 mm MTA Fillapex®. O tempo de endurecimento encontrado nesta pesquisa foi de 1631 'em proporção (10% MTA), 628,4 em proporção (20% MTA), 567' em proporção (30% MTA), 767 em AH Plus e Fillapex MTA não. presou dentro de 6 semanas. Conclusão: concluiu-se que a adição de 10%, 20% e 30% de MTA ao AH Plus não alterou as propriedades do fluxo e o tempo estabelecido

Objective: evaluate the hardening time and flow of AH-PLUS and MTA cement in the proportions of 10%, 20% and 30% in order to add the ability to stimulate the deposition of hard tissue. Material and Methods: For the flow test, 0.5 ml of cement was deposited on a glass plate and another plate was added with an additional charge, after 10 minutes the charge was removed and the diameter of the circle formed by the cement was measured with a digital compass. For the hardening time, cylindrical molds filled with the tested cement were used, kept inside a kiln and Gillmore needle tests were performed on the material at 60 second intervals until the marks were not visible on the surface of the tested cement. Results: In the flow rate, the values obtained were: 41.1mm (10% MTA), 32.86mm (20% MTA), 21.91mm (30% MTA), 24.41mm AHPlus® and 26.47mm MTA Fillapex®. The hardening time found in this survey was 1631 'in proportion (10% MTA), 628.4 in proportion (20% MTA), 567' in proportion (30% MTA), 767 in AH Plus and Fillapex MTA did not. took prey within 6 weeks. Conclusion: it was concluded that the addition of 10%, 20% and 30% of MTA to AH Plus did not change the flow properties and the established time

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The protease kallikrein 4 (KLK4) plays a pivotal role during dental enamel formation by degrading the major enamel protein, amelogenin, prior to the final steps of enamel hardening. KLK4 dysfunction is known to cause some types of developmental defect in enamel but the mechanisms responsible for transient retention of KLK4 in semi-hardened enamel matrix remain unclear. To address contradictory reports about the affinity of KLK4 for enamel hydroxyapatite-like mineral, we used pure components in quasi-physiological conditions and found that KLK4 binds hydroxyapatite directly. Hypothesising KLK4 self-destructs once amelogenin is degraded, biochemical analyses revealed that KLK4 progressively lost activity, became aggregated, and autofragmented when incubated without substrate in both the presence and absence of reducer. However, with non-ionic detergent present as proxy substrate, KLK4 remained active and intact throughout. These findings prompt a new mechanistic model and line of enquiry into the role of KLK4 in enamel hardening and malformation.

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Background: Biomineralization is a significant process performed by living organisms in which minerals are produced through the hardening of biological tissues. Herein, we focus on calcium carbonate precipitation, as part of biomineralization, to be used in applications for environmental protection, material technology, and other fields. A strain GM-1, Microbacterium sp. GM-1, isolated from active sludge, was investigated for its ability to produce urease and induce calcium carbonate precipitation in a metabolic process. Results: It was discovered that Microbacterium sp. GM-1 resisted high concentrations of urea up to 60 g/L. In order to optimize the calcification process of Microbacterium sp. GM-1, the concentrations of Ni2+ and urea, pH value, and culture time were analyzed through orthogonal tests. The favored calcite precipitation culture conditions were as follows: the concentration of Ni2+ and urea were 50 µM and 60 g/L, respectively, pH of 10, and culture time of 96 h. Using X-ray diffraction analysis, the calcium carbonate polymorphs produced by Microbacterium sp. GM-1 were proven to be mainly calcite. Conclusions: The results of this research provide evidence that Microbacterium sp. GM-1 can biologically induce calcification and suggest that strain GM-1 may play a potential role in the synthesis of new biominerals and in bioremediation or biorecovery.

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El endurecimiento de los granos de Phaseolus vulgaris almacenados a alta temperatura y alta humedad relativa es una de las principales limitantes para su consumo. El objetivo de esta investigación fue evaluar por microscopia de barrido electrónico los cambios estructurales ocurridos en los cotiledones y en la testa de los granos endurecidos. Los granos recién cosechados se almacenaron durante doce meses bajo dos condiciones: 5°C-34% HR y 37°C-75% HR. Esta última con el fin de propiciar el endurecimiento. Los granos almacenados crudos y cocidos se liofilizaron y se fracturaron. Las secciones de testa y cotiledones se observaron en un microscopio electrónico JSM-6390. Al cabo de doce meses se constató que los granos almacenados a 37°C-75% HR aumentaron su dureza en un 503%, mientras que los granos almacenados a 5°C-34% HR no incrementaron su dureza significativamente. A nivel microestructural, en los cotiledones de los granos crudos se notaron claras diferencias en el aspecto de la pared celular, en el tamaño del espacio intercelular y en la textura de la matriz proteica. Mientras que en la testa de los granos crudos se evidenciaron diferencias en la compactación de la empalizada y de la capa sub-epidérmica. En los granos cocidos se observó una total separación entre las células de los cotiledones de los granos blandos y una muy limitada separación en los granos duros. Se concluye que las diferencias observadas en los granos duros y blandos, demostraron una participación importante de ambas estructuras, cotiledones y testa, en el endurecimiento de los granos.

The hardening of Phaseolus vulgaris beans stored at high temperature and high relative humidity is one of the main constraints for consumption. The objective of this research was to evaluate by scanning electron microscopy, structural changes in cotyledons and testa of the hardened beans. The freshly harvested grains were stored for twelve months under two conditions: 5 ° C-34% RH and 37 ° C-75% RH, in order to promote hardening. The stored raw and cooked grains were lyophilized and fractured. The sections of testa and cotyledons were observed in an electron microscope JSM-6390. After twelve months, grains stored at 37 ° C-75% RH increased their hardness by 503%, whereas there were no significant changes in grains stored at 5 ° C-34% RH. At the microstructural level, the cotyledons of the raw grains show clear differences in appearance of the cell wall, into the intercellular space size and texture matrix protein. There were also differences in compaction of palisade and sub-epidermal layer in the testa of raw grains. After cooking, cotyledon cells of the soft grains were well separated while these of hard grains were seldom separated. In conclusion, the found differences in hard and soft grains showed a significant participation of both structures, cotyledons and testa, in the grains´ hardening.

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Se presenta un modelo de endurecimiento isotrópico para biomateriales metálicos, el cual emplea un esquema de integración explícita bajo una formulación incremental. Para la implementación computacional se programó un elemento finito de usuario UEL en lenguaje FORTRAN para su ejecución en el software ABAQUS. Con el fin de validar el modelo se resuelven dos ejemplos tipo benchmark y sus resultados son comparados con ANSYS y el UMAT de Dunne y Petrinic para ABAQUS. Finalmente, el modelo es usado para simular la extensión de un stent coronario fabricado en acero inoxidable 316L. Se concluye que el modelo posee un error numérico aceptable teniendo en cuenta que el elemento finito fue programado por completo y no posee ninguna de las optimizaciones de los códigos comerciales. En trabajos futuros el UEL será acoplado con modelos de mecánica de daño continuo para la predicción de la falla por fatiga, cuyo análisis es un estándar básico en la manufactura de stents

A isotropic hardening model is presented for metallic biomaterials, which uses a explicit integration scheme under increasing formula. To computer implementation a finite element from UEL user was programmed in FORTRAN language for its execution in the ABAQUS software. To model validation two examples type benchmark were solved and results are compared with ANSYS and the UMAT of Dunne and Petrinic for ABAQUS. Finally, model is used to simulate the extension of a coronary stent manufactures in 316L stainless steel. We conclude that the model has an acceptable numerical error taking into account that finite element was programmed as a whole and has not any of the optimizations of commercial codes. In future papers the UEL will be coupled with continuous damage mechanics model to predict the failure due to fatigue, whose analysis is a basic standard in stent manufacturing

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This study deals with the behaviour of mixtures of sand and saturated kaolin paste considered as composite materials made of permeable and deformable (with non-linear behaviour) matrix (the kaolin paste) with rigid and impervious inclusions (the sand grains). Oedometric and permeability tests conducted on such mixtures highlight the key role of the state of the clay paste, and show the existence of a threshold of sand grain concentration above which a structuring effect influences both modulus and permeability. At the light of these experiments, the usual and tangent homogenization process (with simplifying assumptions to make the problem manageable) has been applied to estimate the mixture permeability and tangent compressibility. Qualitative and quantitative comparisons with experimental data point out the domain of interest and the limitations of such approaches.

O estudo lida com o comportamento de misturas compostas por areia e uma pasta de caulinita considerada um material composto feito de uma matriz (caulinita) permeável e deformável (com comportamento não-linear) com inclusões rígidas e impermeáveis (grãos de areia). Testes de permeabilidade e odométricos conduzidos nestas misturas enfatizam o papel chave de estado da pasta argilosa e mostram a existência de uma concentração crítica de grãos de areia com efeito estruturante que influencia o módulo e a permeabilidade. Sob a luz destes experimentos o processo de homogeneização usual e tangente (com hipóteses simplificadoras para tornar o problema tratável) foi aplicado para estimar a permeabilidade da mistura e a compressibilidade tangente. Comparações qualitativas e quantitativas com dados experimentais apontam o domínio de interesse bem como a limitação destas abordagens.

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Eucalyptus globulus Labill is one of the most planted species in Chile, because of its fast growth and superior pulp qualities. Nevertheless, the incidence of drought and frost damage immediately after planting is frequent. The purpose of this work was to study the effect of drought hardening on frost resistance and on variations in morphological traits that may increase drought resistance at nursery phase in four genotypes of E. globulus Labill. Drought hardening treatments consisted in induced water stress by watering restriction, until pre-dawn stem xylem water potentials (Psi pd) reached -0.2, -1.8 and -2.6 MPa. Two water stress-rewatering cycles were applied during 54 days of hardening. Plant and root biomasses were affected by the interaction of drought hardening and genotypes. The rest of morphological and alometrical traits were affected independently by drought or genotype. Plant height, leaf area, specific leaf area (SLA), stem, and leaf biomasses decreased with drought hardening, while collar diameter was not affected. Genotypes responded differentially to drought hardening in plant height, leaf area, SLA, and stem, and leaf biomasses. Ice nucleation temperature (INT), and freezing temperatures (FRT), and 50 percent freezing damage index of leaves (LT50) were affected by the interaction between drought hardening and genotypes. EG-13, EG-23 and EG-22 genotypes became freezing tolerant with drought hardening (-2.6 MPa). Additionally, EG-14 genotype increased its freezing resistance at -1.8 MPa. Therefore, freezing resistance levels and mechanism depend on genotype and drought hardening treatment. The success in tree breeding by genetic selection should be facilitated by improved understanding of the physiology of stress resistance development and survival during water supply limitations. The knowledge of morphological and freezing resistance dependency on the interaction between genotype and drought hardening may be useful...

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Pesquisas acerca das modificações estruturais e fisiológicas inerentes ao processo de micropropagação são fundamentais para compreender os efeitos desta técnica, desenvolver protocolos mais eficientes e, sobretudo, reduzir perdas ex vitro. O objetivo neste trabalho foi avaliar e quantificar as modificações na anatomia foliar de bananeiras provenientes de micropropagação, durante a fase de aclimatização em casa de vegetação. Para tanto, brotações axilares de bananeira cv. Japira, provenientes da multiplicação in vitro, foram enraizadas em meio MS, acrescido de ANA (1mg L-1) e ágar (6g L-1), e mantidas à temperatura de 25°C±2°C e 16 horas de irradiância a 35µmol m-2 s-1, por 35 dias. Posteriormente, as plantas foram submetidas a diferentes períodos de aclimatização (zero, 21, 42, 63, 84 e 120 dias) e avaliadas quanto à anatomia, por meio de seções transversais e paradérmicas foliares. O delineamento experimental foi inteiramente casualizado. Verificou-se que as maiores alterações anatômicas ocorrem após 42 dias do transplantio ex vitro, com acentuado espessamento dos parênquimas clorofilianos e limbo foliar, bem como diferenciação da maioria dos tecidos. Quanto aos estômatos, estes estão distribuídos em ambas às faces da epiderme, com maior número na face abaxial e em folhas oriundas de primórdios foliares formados in vitro.

Researches about structural and physiological modifications in different stages of the micropropagation are fundamental to understand the effects of this technology to improve protocols and to reduce losses in the acclimatization. The objective of this study was to assess and to quantify the variations in the foliar anatomy of micropropagated banana plants during the ex vitro acclimatization in greenhouse. Thus, axillary buds from in vitro multiplication of Japira cultivar, were rooted in MS medium, added of NAA (1mg L-1) and agar (6g L-1), and kept at room temperature (25°C ±2°C) under 16 hours photoperiod and irradiation of 35µmol m-2 s-1, for 35 days. Subsequently, the plants were submitted to different acclimatization periods (zero, 21, 42, 63, 84 e 120 days) being the leaf anatomy of the plants evaluated by transversal and paradermal sections. A completely randomized design was used. The largest anatomical alterations it were verified after 42 days of the transplantation to ex vitro conditions, with pronounced thickness of chlorophyllian parenchyma and leaf blade, as well, as the differentiation of the majority of foliar tissues. The stomata were distributed on both sides of the leaves, with higher number on the undersurface and on leaves formed from in vitro foliar primordia.

RESUMO

Researches about structural and physiological modifications in different stages of the micropropagation are fundamental to understand the effects of this technology to improve protocols and to reduce losses in the acclimatization. The objective of this study was to assess and to quantify the variations in the foliar anatomy of micropropagated banana plants during the ex vitro acclimatization in greenhouse. Thus, axillary buds from in vitro multiplication of Japira cultivar, were rooted in MS medium, added of NAA (1mg L-1) and agar (6g L-1), and kept at room temperature (25°C ±2°C) under 16 hours photoperiod and irradiation of 35µmol m-2 s-1, for 35 days. Subsequently, the plants were submitted to different acclimatization periods (zero, 21, 42, 63, 84 e 120 days) being the leaf anatomy of the plants evaluated by transversal and paradermal sections. A completely randomized design was used. The largest anatomical alterations it were verified after 42 days of the transplantation to ex vitro conditions, with pronounced thickness of chlorophyllian parenchyma and leaf blade, as well, as the differentiation of the majority of foliar tissues. The stomata were distributed on both sides of the leaves, with higher number on the undersurface and on leaves formed from in vitro foliar primordia.

Pesquisas acerca das modificações estruturais e fisiológicas inerentes ao processo de micropropagação são fundamentais para compreender os efeitos desta técnica, desenvolver protocolos mais eficientes e, sobretudo, reduzir perdas ex vitro. O objetivo neste trabalho foi avaliar e quantificar as modificações na anatomia foliar de bananeiras provenientes de micropropagação, durante a fase de aclimatização em casa de vegetação. Para tanto, brotações axilares de bananeira cv. Japira, provenientes da multiplicação in vitro, foram enraizadas em meio MS, acrescido de ANA (1mg L-1) e ágar (6g L-1), e mantidas à temperatura de 25°C±2°C e 16 horas de irradiância a 35µmol m-2 s-1, por 35 dias. Posteriormente, as plantas foram submetidas a diferentes períodos de aclimatização (zero, 21, 42, 63, 84 e 120 dias) e avaliadas quanto à anatomia, por meio de seções transversais e paradérmicas foliares. O delineamento experimental foi inteiramente casualizado. Verificou-se que as maiores alterações anatômicas ocorrem após 42 dias do transplantio ex vitro, com acentuado espessamento dos parênquimas clorofilianos e limbo foliar, bem como diferenciação da maioria dos tecidos. Quanto aos estômatos, estes estão distribuídos em ambas às faces da epiderme, com maior número na face abaxial e em folhas oriundas de primórdios foliares formados in vitro.

RESUMO

Researches about structural and physiological modifications in different stages of the micropropagation are fundamental to understand the effects of this technology to improve protocols and to reduce losses in the acclimatization. The objective of this study was to assess and to quantify the variations in the foliar anatomy of micropropagated banana plants during the ex vitro acclimatization in greenhouse. Thus, axillary buds from in vitro multiplication of Japira cultivar, were rooted in MS medium, added of NAA (1mg L-1) and agar (6g L-1), and kept at room temperature (25°C ±2°C) under 16 hours photoperiod and irradiation of 35µmol m-2 s-1, for 35 days. Subsequently, the plants were submitted to different acclimatization periods (zero, 21, 42, 63, 84 e 120 days) being the leaf anatomy of the plants evaluated by transversal and paradermal sections. A completely randomized design was used. The largest anatomical alterations it were verified after 42 days of the transplantation to ex vitro conditions, with pronounced thickness of chlorophyllian parenchyma and leaf blade, as well, as the differentiation of the majority of foliar tissues. The stomata were distributed on both sides of the leaves, with higher number on the undersurface and on leaves formed from in vitro foliar primordia.

Pesquisas acerca das modificações estruturais e fisiológicas inerentes ao processo de micropropagação são fundamentais para compreender os efeitos desta técnica, desenvolver protocolos mais eficientes e, sobretudo, reduzir perdas ex vitro. O objetivo neste trabalho foi avaliar e quantificar as modificações na anatomia foliar de bananeiras provenientes de micropropagação, durante a fase de aclimatização em casa de vegetação. Para tanto, brotações axilares de bananeira cv. Japira, provenientes da multiplicação in vitro, foram enraizadas em meio MS, acrescido de ANA (1mg L-1) e ágar (6g L-1), e mantidas à temperatura de 25°C±2°C e 16 horas de irradiância a 35µmol m-2 s-1, por 35 dias. Posteriormente, as plantas foram submetidas a diferentes períodos de aclimatização (zero, 21, 42, 63, 84 e 120 dias) e avaliadas quanto à anatomia, por meio de seções transversais e paradérmicas foliares. O delineamento experimental foi inteiramente casualizado. Verificou-se que as maiores alterações anatômicas ocorrem após 42 dias do transplantio ex vitro, com acentuado espessamento dos parênquimas clorofilianos e limbo foliar, bem como diferenciação da maioria dos tecidos. Quanto aos estômatos, estes estão distribuídos em ambas às faces da epiderme, com maior número na face abaxial e em folhas oriundas de primórdios foliares formados in vitro.

RESUMO

Conduziu-se este trabalho, com o objetivo de induzir a estímulo do comportamento fotoautotrófico durante o enraizamento in vitro em brotações de Annona glabra L. Brotações oriundas de cultivo em tubos fechados com tampa e película de PVC (cultivo sem aeração), com tampa sem a película de PVC e tampão de algodão (cultivo com aeração) foram inoculadas em meio WPM suplementado com 4,9 µ M de AIB e 164,4mM de carvão ativado na presença (58,42mM) ou ausência de sacarose. Durante o enraizamento, foram mantidas as mesmas condições de vedação dos tubos de ensaio em que as brotações foram induzidas. Após a inoculação, os tubos contendo os explantes foram mantidos em sala de crescimento sob radiação fotossintética ativa de 45-56 µ mol.m-2.s-1 a 25±3ºC. Os resultados mostraram que o enraizamento das brotações de A. glabra não dependeu do suprimento de sacarose no meio de cultura, em tubos fechados com o tampão de algodão ou tampa plástica sem PVC. A aeração dos tubos de ensaio trouxe incrementos de significativos (até 250 por cento) na matéria seca radicular. A indução de raízes secundárias (laterais) em A. glabra só ocorreu em culturas com aeração, independentemente da presença ou ausência de sacarose no meio de cultura. Com os resultado desse experimento, conclui-se que o estímulo do comportamento fotoautotrófico em A.glabra pode ser obtido com sucesso durante a fase de enraizamento in vitro.

The objective of the present work was to evaluate whether Annona glabra L. shoots are able to acquire the photoautotrophic behavior during the in vitro rooting. In vitro A. glabra shoots originated from cultures in vessels sealed with cap and PVC film (culture without aeration), cap without PVC film or cotton tampon (cultures with aeration), were inoculated in WPM medium supplemented with 4.9 µ M IBA and 164,4mM activated charcoal in the presence (58.42mM) or absence of sucrose. During rooting, the same conditions in which shoots were induced were maintained. After inoculation, the tubes with explants were maintained in growth room under photosynthetic active radiation of 45-56 µ mol.m-2.s-1 and of temperature 25±3ºC. The results showed that the rooting of A. glabra shoots do not depend on the supply of sucrose into culture medium, in vessel with aeration. Aeration of cultures brought expressive increments of dry weight of roots (up to 250 percent). The induction of secondary (side) roots was found only in cultures with aeration, independently of sucrose presence. One concluded that the acquisition of the photoautotrophic behavior in A. glabra may be obtained with success during the in vitro rooting phase.

RESUMO

Cattleya trianae is an endemic species from the tropical rainforest in the Colombian Andes. Its survival is currently threatened due to habitat loss and commercial overexploitation. This study evaluates ten substrates, some organic (pine bark, coconut fiber and wood shavings), some inert icopor (polystyrene foam), vegetable coal and their combinations, and the effects these have on morphometric and phenotypic traits in the hardening phase of 250 plants of C. trianae cultivated in vitro. Recorded data include percent survival, length of longest leaf, biomass (wet weight) and number of roots and leaves at the beginning and at the end of the experiment. After the hardening phase, the plants were taken to a greenhouse and later to the natural environment. Coconut fiber alone or mixed in equal parts with pine bark and coal was the most efficient substrate when percent survival (80±SE=0.3742), biomass, and leaf length were evaluated. Hardened plants displayed qualitative characteristics such as vigor, hardness and waxy texture, strength of green coloration in the leaves, and velamen formation. Under greenhouse conditions, plants grew better with filtered light, relative humidity bordering on 80 %, permanent aeration, misting with water, and an average temperature of 25±2 °C. Invigorated plants were firmly anchored on their host trees. Rev. Biol. Trop. 55 (2): 681-691. Epub 2007 June, 29.

Cattleya trianae es una especie endémica de los bosques tropicales de los Andes colombianos. Actualmente se encuentra amenazada por la disminución de su hábitat natural y la sobreexplotación con fines comerciales. En este estudio se evaluó el efecto de diez tratamientos con sustratos biológicos (corteza de pino, fibra de coco y viruta) e inertes (esferitas de "icopor" y carbón vegetal) en diferentes combinaciones, sobre aspectos morfométricos y fenotípicos en la etapa de endurecimiento de 250 vitroplantas de C. trianae. Se registró porcentaje de supervivencia, longitud de la hoja, biomasa en peso fresco, número de raíces y hojas al inicio y al final del experimento. Al finalizar la fase de endurecimiento, las vitroplantas fueron llevadas a invernadero y posteriormente a ambiente natural. La fibra de coco sola ó mezclada en partes iguales con pino y carbón vegetal, fue el sustrato más eficiente cuando se evaluó el porcentaje de supervivencia (80 % ±SE=0.3742), biomasa en peso fresco y longitud de hoja. Las plantas endurecidas mostraron características cualitativas como vigorosidad, textura coriácea y cerosa, verdor intenso en sus hojas y velamen. En condiciones de invernadero las plantas se desarrollan mejor con luz filtrada, humedad relativa alrededor del 80 %, aireación continua, nebulización y temperatura promedio de 25±2 °C. Las plantas vigorizadas mostraron buen anclaje y adaptación en árboles.

Assuntos