• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 248
  • 97
  • 23
  • 12
  • 9
  • 5
  • 5
  • 4
  • 4
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 453
  • 172
  • 51
  • 44
  • 39
  • 34
  • 30
  • 30
  • 29
  • 28
  • 28
  • 26
  • 26
  • 24
  • 24
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Propolio etanolinių ekstraktų cheminės sudėties tyrimas ir antioksidacinio aktyvumo vertinimas / Analysis of chemical composition and antioxidant activity of ethanolic extracts of propolis

Banionytė, Inga 09 June 2009 (has links)
Propolis (bičių pikis, bičių klijai) yra sakinga medžiaga, kurią bitės surenka nuo tuopų, beržų, liepų ar kitų augalų (priklausomai nuo tos geografinės zonos augmenijos). Propolio farmakologinis poveikis yra labai įvairus, todėl jis nuo seno populiarus liaudies medicinoje ir traukia mokslininkų dėmesį (ypač nuo XX a. 7 dešimtmečio). Viena iš svarbiausių propolio savybių yra stiprus antioksidacinis aktyvumas. Tyrimo tikslas - nustatyti bei palyginti pagrindinių veikliųjų medžiagų kiekius propolio etanoliniuose ekstraktuose, įvertinti jų antioksidacinį aktyvumą. Pritaikius maceracijos metodą, buvo pagaminti skystieji propolio etanoliniai ekstraktai (etanolis 50%, 60%, 70%, 80% ir 96% koncentracijos). Buvo įvertinta ekstraktų kokybė gravimetriniu, spektrofotometriniu bei efektyviosios skysčių chromatografijos su diodų matricos ir masių spektrometrijos detektoriais (ESCh-DAD-MS) metodais. Pritaikius efektyviosios skysčių chromatografijos ir masių spektrometrijos metodą, nustatyta, kad viena iš dominuojančių fenolinių rūgščių propolio etanoliniuose ekstraktuose yra ferulo rūgštis. Todėl nustatant fenolinių junginių kiekį propolio etanoliniuose ekstraktuose spektrofotometriškai, kaip standartas buvo panaudota ferulo rūgštis. Bendras fenolinių junginių kiekis gautas apie 10 kartų didesnis, nei naudojant pinocembrino ir galangino mišinį (2:1). Daugiausiai fenolinių junginių nustatyta ekstraktuose, gautuose ekstrahuojant 70%, 80% bei 96% etanoliu. Buvo atliktas antioksidacinio... [toliau žr. visą tekstą] / Propolis (bee glue) is a resinous material that honeybees collect from poplar, birch or other plants (the plant source depends on the geographic origin of propolis). Because of its popularity in folk medicine, propolis has become the subject of intense pharmacological and chemical studies for the last 30 years. Numerous studies have proven its versatile pharmacological activities. One of the most important is its antioxidant activity. The objective of this study was to identify and compare the main active substances in the ethanolic extracts of propolis and to evaluate their antioxidant activity. The classical maceration method was used for the production of liquid ethanolic extracts of propolis (the concentration of used ethanol: 50%, 60%, 70%, 80% and 96%). The quality of popolis was evaluated by gravimetric, spectrophotometric and High Performance Liquid Chromatography with Diode Array and Mass Spectrometric detectors (HPLC-DAD-MS) methods. The results of the HPLC-DAD-MS analysis showed that one of the main phenolic acids in the ethanolic extracts of propolis is ferulic acid. That was the reason for using it as a standard in the spectrometric analysis of total phenolic compounds. Spectrophotometric method showed about 10 times higher results than the analysis with the standard of pinocembrin and galangin mixture (2:1). The highest concentrations of phenolic compounds were found in the extracts made with the ethanol of 70%, 80% and 96% concentrations. The antioxidant... [to full text]
72

Applications of spice extracts and other hurdles to improve microbial safety and shelf-life of cooked, high fat meat products (doner kebab)

Al-Kutby, Sahar January 2012 (has links)
There is a growing demand for safe and convenient meat products. The effect of natural spice extracts incorporated with other hurdles for controlling pathogenic bacteria and extending the shelf life of RTE doner kebab were investigated. A comprehensive literature review was undertaken to establish the status of microbial risk, use of additives, knowledge on oxidative deterioration and HACCP associated with meat products. The in vitro antioxidant and antibacterial activities of spice extracts were screened and compared. Cinnamon, clove, and sumac alcoholic extracts demonstrated strong antimicrobial effect, however, rosemary proved effective as antioxidant in a lamb fat model. An accelerated shelf life study on a model system indicated that storage temperature was the most critical factor affecting lipid oxidation, which was effectively delayed by vacuum packaging and rosemary extracts. The effects of spice extracts, packaging and storage time on physiochemical, microbiological, and sensory attributes of doner kebab were evaluated. Application of rosemary and cinnamon extracts significantly reduced TVC, inhibited LAB, and retarded lipid oxidation rate. Sensory evaluation by a consumer panel indicated that only taste and spiciness perception was significantly different between treatments. A challenge test against Listeria monocytogenes showed significant differences between control and spice treatments at day 28. Strong inhibitory effects were associated to high levels of cinnamon particularly when applied after cooking. The effect of heat treatment and sumac (Rhus coriaria) on Bacillus cereus and Clostridium perfringens inactivation was evaluated on a doner kebab prototype. Addition of sumac significantly reduced D-values and z-values for both organisms in comparison to the control. The investigation of the effect of spice extracts, and environmental conditions on changes in growth kinetic parameters for L. monocytogenes and Salmonella Typhimurium showed that spice extracts are highly significant. For both microorganisms, Mumax was reduced as salt and spice concentrations increased, and pH levels decreased. This study shows that spice extracts incorporated with other hurdles can help to maintain safe and good quality RTE doner kebab.
73

Optimization of in vitro transcription/translation conditions for in vitro compartmentalization studies and synthesis of 4-fluorohistidine

Ring, Christine 01 January 2017 (has links)
Genetic code expansion allows the incorporation of non-canonical amino acids with a variety of new functional groups: fluorescent amino acids,1-3 azides,4-6 alkynes,5-10 and photocrosslinkers.4,11,12 This incorporation requires the evolution of new tRNA/aminoacyl tRNA sythetase pairs. Traditionally screenings of novel tRNA/aminoacyl tRNA synthetase pairs have been done in vivo. While these in vivo screenings have proven robust, they are limited in multiple ways: non-canonical amino acids (ncAAs) must be nontoxic and bioavailable. Furthermore, library size is limited by transformation efficiency. Lastly, in vivo screenings require substantial amounts of the target ncAA, which is often not available in large masses. In vitro screenings bypass these limitations: toxicity and bioavailibilty are no longer concerns. Library size can be expanded by several orders of magnitude as we are no longer limited by transformation efficiency. Lastly, because in vitro transcription/translation reactions are routinely conducted on the μL scale, ncAA usage can be minimized. We set out to use in vitro compartmentalization to further expand the code. In an in vitro compartmentalization screening, the water droplets in a water-in-oil emulsion serve as separate reaction chambers in which individual library members are transcribed and translated. Here we report optimization of S30 transcription/translation reactions. Optimizations include cell lysis method, reaction temperature, template amount, and T7 RNA polymerase amounts. Yields remained low and we transistioned into the use of PURExpress. Fluorohistidines are isosteric with histidine, but not isoelectronic.13 This change in environment results in a reduction of pKa. We set out to synthesize 4-fluorohistidine to use as a pH probe in several target proteins. A synthesis of 4-fluorohistidine was published in 1973.14,15 We were able to improve upon this synthesis by reducing cost and improving yield of a key step in the reaction. Next, small peptides with polyhistidine tags were translated in vitro using our 4-fluorohistidine. We are calling this polyhistidine tag incorporating 4-fluorohistidine our “hexafluorohistag.” Because of the reduced pKa of the 4-fluorohistidine, the hexafluorohistag showed affinity to Nickel-NTA resin even at reduced pH. This allowed for the purification of hexafluorohistagged peptides in the presence of traditional polyhistidine-tagged peptides.
74

Using Aqueous Soil Extracts to Study Organic Matter Leaching From Soils of Different River Corridor Land Covers in Vermont

Hampsch, Alyson 01 January 2016 (has links)
Soils represent an important terrestrial carbon (C) sink, storing up to three times the amount of atmospheric C, however climate and land use changes may transform soils into C sources. River corridor (RC) soils and associated C are at risk to become mobilized by erosion such as bank failure and scour events. Once soil-derived organic C is transferred into the stream, microbial processes and photodegradation of the dissolved, labile (or bioavailable) fractions can lead to the production of CO2, which can evade and increase atmospheric CO2 levels. Because predicted increases in heavy precipitation will likely increase this type of riverine erosion, it is important to better understand the potential for the release of bioavailable C from RCs. One objective of this thesis was therefore to identify and characterize representative samples of soils from a typical Vermont RC for common land covers and simulate the production of dissolved organic matter (DOM) during riverine soil erosion. Field sites representative of typical agricultural and forested land uses were selected based on the analysis of 106 existing samples and resampled multiple times over the summer of 2015. Production of DOM from riverine erosion was simulated using aqueous soil extracts (ASE), where soil and water were shaken at fixed ratios followed by the separation of the extract. To study the characteristics of these extracts (which serve as analogue of stream water after erosion), water extractable C (WEOC) concentrations, water extractable nitrogen, fluorescence properties of DOM, and bioavailability were determined. Results indicated a common, dominantly terrestrial source material for all land covers, but C concentrations and fluorescence properties differed. High but variable amounts of soil organic C and WEOC were observed in agricultural riparian and agricultural stream bank samples, and lower concentrations in agricultural field, forest, forest riparian, and forest stream banks. WEOC bioavailability was high in all agricultural land covers and low in forested land covers. Because this study is the first in which ASE are used as analogues for stream water after riverine erosion, a second objective was to test laboratory methods used in this study for their effect on WEOC, fluorescence properties, and bioavailability. Specifically, the effects of soil drying, soil storage, and the effects of the extraction solution were tested. For this, ASE were prepared from soils that were field moist, dried, and after two years of storage. In addition, dried soils were extracted using different solutions including a salt solution, river water, and double deionized (DDI) water. Results indicated WEOC concentration and microbial humic-like fluorescence from extracts of dried soils were higher than those in extracts of field moist soils, while WEOC concentration and microbial humic-like fluorescence was highest in extracts of soils stored long term. In addition, the bioavailability of WEOC was higher in dried soils than field moist soils. The extraction solutions of DDI water and river water produced DOM with similar fluorescence properties, while the salt solution extracted a different, less humified pool of C. Overall, the ASE methods used in this study are effective in simulating stream bank erosion and subsequent C release into stream water, however the effects of drying the soils need to be considered when assessing DOM.
75

Etude toxinologique du venin de fourmis exotiques : identification et caractérisation d’un peptide antimicrobien / Study of exotic ants venoms : identification and characterization of an antimicrobial peptide

Rifflet, Aline 23 May 2012 (has links)
Les venins animaux, par leur richesse biochimique et la diversité de leurs cibles moléculaires, sont une source importante de molécules dont les applications potentielles sont nombreuses. La recherche de nouveaux médicaments pour remplacer certains antibiotiques devenus inefficaces face à l'apparition de résistances, est un axe fort de la recherche pharmacologique. Depuis plus de 40 ans, la découverte de toxines animales montre que les animaux venimeux peuvent être les « pharmaciens du futur ». Le venin de fourmis est encore peu étudié. Seul celui de quelques espèces a été exploré, avec à chaque fois la mise en évidence de toxines originales. L'objectif de cette thèse a été l'étude du venin de fourmis exotiques sur la base d'une approche pluridisciplinaire qui combine l'analyse biochimique et la toxinologie. Les travaux se sont articulés autour de deux axes principaux : (1) Recherche d'activités biologiques sur insectes et bactéries ; (2) Fractionnement des venins par des techniques séparatives et analyse biochimique des peptides isolés par spectrométrie de masse. Deux espèces de fourmis ont été choisies en fonction de leur mode de vie : Crematogaster striatula, une espèce arboricole et Tetramorium bicarinatum, une espèce terricole. Les différentes activités biologiques de leurs sécrétions venimeuses ont été conduites par test MTT. Le liquide de Dufour de C. striatula en plus de sa capacité à éloigner les espèces concurrentes montre une capacité à paralyser les termites de manière irréversible. Concernant le venin de T. bicarinatum, deux peptides ont été isolés et identifiés par spectrométrie de masse. La bicarinaline, peptide de 20 acides aminés et amidé à son extrémité C-terminale, s'est démarqué par son action antibactérienne à large spectre. Testée sur deux souches de staphylocoques, ce peptide se révèle aussi efficace voire plus puissant que la méllitine, peptide antimicrobien du venin d'abeille. La bicarinaline apparaît comme un candidat potentiel pour la conception de nouveaux traitements antibiotiques. / Animal venoms, by their biochemical richness and diversity of molecular targets, are a highly significant source of new molecules, with numerous potential applications. A major thrust of present pharmacological research now concerns drugs to replace certain antibiotics, proven ineffective due to the appearance of resistant strains. And discoveries of animal toxins over the past 40 years or more, have shown that venomous species could be the « pharmacists of the future », with only a few species of ants' venoms having been studied, but each time resulting in the description of original toxins. The aim of this thesis has been to study the venom of tropical ants using a multidisciplinary approach combining biochemical analysis and toxinology, centred on two main areas: (1) Research into their biological activity on insects and bacteria; (2) Fractionation of venoms using separative techniques, plus biochemical analysis of the peptides isolated using mass spectrometry. Two species of ant have been chosen based on their lifestyles: Crematogaster striatula is arboricolous and Tetramorium bicarinatum, terricolous, and the different biological activities of their crude venoms have been investigated using the MTT test. The Dufour liquid of C. striatula, in addition to its ability to scare away competitors, can definitively paralyse termites. For the venom of T. bicarinatum, two peptides have been isolated, and identified using mass spectrometry. Bicarinalin, a short 20 amino acid residues C-terminally amidated peptide, was notable for its wide spectrum antibacterial activity which, when tested on two Staphylococcus strains, proved to be at least if not more potent than mellitin, the antimicrobial peptide from bee venom. Bicarinalin would thus appear to be a good candidate for the development of new antibiotic drugs.
76

Regulation of DNA Double Strand Break Response

Chen, Chen January 2014 (has links)
<p>To ensure genomic integrity, dividing cells implement multiple checkpoint pathways during the course of the cell cycle. In response to DNA damage, cells may either halt the progression of the cycle (cell cycle arrest) or undergo apoptosis. This choice depends on the extent of damage and the cell's capacity for DNA repair. Cell cycle arrest induced by double-stranded DNA breaks relies on the activation of the ataxia-telangiectasia (ATM) protein kinase, which phosphorylates cell cycle effectors (e.g., Chk2 and p53) to inhibit cell cycle progression. ATM is an S/T-Q directed kinase that is critical for the cellular response to double-stranded DNA breaks. Following DNA damage, ATM is activated and recruited to sites of DNA damage by the MRN protein complex (Mre11-Rad50-Nbs1 proteins) where ATM phosphorylates multiple substrates to trigger a cell cycle arrest. In cancer cells, this regulation may be faulty and cell division may proceed even in the presence of damaged DNA. We show here that the RSK kinase, often elevated in cancers, can suppress DSB-induced ATM activation in both Xenopus egg extracts and human tumor cell lines. In analyzing each step in ATM activation, we have found that RSK disrupts the binding of the MRN complex to DSB DNA. RSK can directly phosphorylate the Mre11 protein at Ser 676 both in vitro and in intact cells and can thereby inhibit loading of Mre11 onto DSB DNA. Accordingly, mutation of Ser 676 to Ala can reverse inhibition of the DSB response by RSK. Collectively, these data point to Mre11 as an important locus of RSK-mediated checkpoint inhibition acting upstream of ATM activation.</p><p>The phosphorylation of Mre11 on Ser 676 is antagonized by phosphatases. Here, we screened for phosphatases that target this site and identified PP5 as a candidate. This finding is consistent with the fact that PP5 is required for the ATM-mediated DNA damage response, indicating that PP5 may promote DSB-induced, ATM-dependent DNA damage response by targeting Mre11 upstream of ATM.</p> / Dissertation
77

Estudo in vitro do potencial estimulatório do extrato de semente de uva (GSE) na atividade funcional e na expressão gênica de células odontoblastoides da linhagem MDPC-23 / In vitro study of the stimulatory potential of grape seed extract (GSE) in the functional activity and gene expression of odontoblast-like cells from MDPC-23 line

Rezende, Patricia Helena Colbachini 29 June 2018 (has links)
Apesar da capacidade regenerativa da dentina já ser bem estabelecida, este processo pode ser insuficiente no caso de injúrias decorrentes de traumas e/ou lesões cariosas extensas, podendo levar à exposição pulpar e perda de sua vitalidade. Assim, pesquisas recentes no campo da engenharia tecidual têm identificado materiais e substâncias que poderiam ser utilizadas como biomodificadores da dentina e auxiliares na regeneração do complexo dentina-polpa. Entre eles estão os extratos ricos em proantocianidina, um composto fenólico bioativo presente no extrato de semente de uva (GSE). Assim, o objetivo deste trabalho foi avaliar o potencial estimulatório de quatro concentrações crescentes do GSE na atividade funcional de células odontoblastoides. Foram utilizadas células de camundongo da linhagem MDPC-23, cultivadas em garrafas de cultura até a subconfluência. Em seguida, as células foram cultivadas em placas de 24 poços em uma concentração de 104/poço e divididas em cinco grupos: células sem adição do GSE, células + 0.1 µg/mL de GSE; células + 1 µg/mL de GSE; células + 10 µg/mL de GSE; células + 20 µg/mL de GSE. Após 3, 7 e 10 dias, foram analisados os seguintes parâmetros: proliferação e viabilidade celular, detecção e atividade de fosfatase alcalina, quantidade de proteína total, detecção e quantificação de nódulos mineralizados, expressão quantitativa dos genes Alp, Col1a1 e Dmp1 por meio de PCR em tempo real e sua expressão proteica correspondente por meio de imunolocalização. Os dados obtidos foram analisados quanto à normalidade e submetidos aos testes estatísticos ANOVA e Kruskal-Wallis, com nível de significância estabelecido em 5%. Os resultados mostraram proliferação e viabilidade celular com as concentrações mais baixas de GSE (0,1 e 1 µg/mL), assim como a atividade de síntese de proteínas totais e da fosfatase alcalina. A deposição de nódulos mineralizados foi significativamente maior com a concentração de 1 µg/mL do extrato. Esta mesma concentração favoreceu a expressão quantitativa dos genes Alp, Col1a1 e Dmp1 e a secreção das proteínas correspondentes vistas por imunolocalização. Conclui-se que baixas concentrações do extrato de semente de uva podem influenciar e favorecer a atividade de células odontoblastoides, contribuindo para a regeneração dentinária, devido à suas características antioxidantes e biomineralizadoras / The process of dentinogenesis generally involves several steps of cell differentiation, culminating with an extracellular matrix very similar to bone tissue. Dentin regeneration may be necessary in cases of pulp exposure, root resorption and carious lesions. Studies on functional regeneration of lost tissues are being carried on recently, based on the presence of cells, scaffolds and/or substances that induce cell proliferation and differentiation. Among the several substances which can interact with cell metabolism are the extracts rich in proanthocyanidin, bioactive phenolic compounds present in fruits, vegetables and seeds. The purpose of this project is to evaluate the stimulatory potential of four different concentrations of grape seed extract (GSE) in the functional activity of odontoblast-like cells. MDPC-23 cell line was seeded in culture flasks until subconfluence followed by cell seeding in 24-well culture plates in the concentration of 104/well and divided in five groups: 1) cells without GSE, 2) cells + 0,1 µg/mL of GSE; 3) cells + 1 µg/mL of GSE; cells + 10 µg/mL of GSE and cells + 20 µg/mL of GSE. After 3, 7 and 10 days, there were evaluated the following parameters: cell proliferation and differentiation, ALP detection and activity, total protein content, mineralization detection and quantification, as well as the expression of genes Alp, Col1a1 and Dmp1 through Real Time PCR and their corresponding proteins by means of immunolocalization. Data were analyzed by ANOVA and Kruskal-Wallis statistical tests, with significance level set at 5%. The results demonstrated cell proliferation and viability with low GSE concentrations (0,1 and 1 µg/mL), as well as total protein content and ALP activity. Deposition of mineralized nodules was significantly increased with the GSE concentration of 1 µg/mL. The same concentration favoured the expression of genes Alp, Col1a1 and Dmp1 as well as the corresponding proteins. It is concluded that low concentrations of grape seed extract may influence functional activity of odontoblast- like cells, contributing to dentin regeneration by means of its antioxidant and biomineralizing properties
78

Vliv rýžového extraktu jako nové kluzné látky na lisovatelnost mikrokrystalické celulosy / The influence of rice extract as a new lubricant on the compressibility of microcrystalline cellulose

Bučková, Lenka January 2019 (has links)
Charles University, Faculty of Pharmacy in Hradci Králové Department of: Department of Pharmaceutical Technology Consultant: PharmDr. Pavel Ondrejček, Ph.D. Student: Lenka Bučková Title of Thesis: The influence of rice extract as a new lubricant on the compressibility of microcrystalline cellulose In this thesis the rice extract was studied as a new lubricant. Primarily its influence on microcrystalline cellulose compressibility was studied. Its effects were compared to sodium stearylfumarate and colloidal silicon dioxide. The used lubricants were wixed with the filler in the concentrations ranging from 0.1 to 1%. The mass flow rate was evaluated in the filler itself and its mixtures. Subsequently, the tablets were made using the compression forces ranging from 2.5 to 7.5kN. The compaction process was evaluated using the force- displacement method. Furthermore, the tablet hardness, friability and disintegration time was tested. The results showed that the rice extract can be used as lubricant for the used model filler. Unlike other evaluated glidants, it must be used at concentrations up to 0,25%. The use of higher concentrations does not improve the flow properties of tableting mixtures. In addition, material elasticity and tablet friability increases and tablet hardness decreases. On the other...
79

Vliv velikosti částic na lisovatelnost laktosy / The effect of particle size on lactose compressibility

Havlíková, Natálie January 2019 (has links)
Charles University in Prague, Faculty of Pharmacy in Hradci Králové Department of: Pharmaceutical technology Consultant: PharmDr. Pavel Ondrejček, Ph.D. Student: Natálie Havlíková Title of Thesis: The effect of particle size on lactose compressibility It is known that the particle size of the compressed material plays an important role in the manufacture of tablets. It affects the properties of intermediate and final products. In this thesis the properties of tablets made of two lactose types, which were used as model fillers, were studied. These were Tablettose® 80 and Lactopress® Anhydrous. In both lactose types, five sieved size fractions of the particle size ranging from 9 to 346µm and their original unsieved mixture were used. The compaction forces ranging from 2 to 10kN were used for tablet preparation. Magnesium stearate was used for external lubrication. The evaluation of the prepared tablets was done mainly by using the pharmacopoeial methods. The evaluated parameters were friability, disintegration time and hardness. Furthermore, the elasticity of the tablets and the evaluation using the force-displacement method parameters were assessed. From the results of this work, it is not possible to unambiguously determine the advantage of one particular fraction size in the comparison to the...
80

Otimização da produção de mudas clonais de eucalipto com o uso de bioestimulantes / The optimization to producing eucalyptus clones with biostimulants

Leone, Gabriela Ferraz 15 March 2019 (has links)
Devido à grande importância que o gênero Eucalyptus apresenta, cada vez mais estudos relacionados à otimização da propagação de espécies do gênero vêm sendo conduzidos. Os principais entraves estão relacionados à sua clonagem e a recalcitrância que algumas espécies apresentam ao enraizamento e, por essa razão, o presente trabalho teve como objetivo avaliar o uso de bioestimulantes na mini e microestaquia de Eucalyptus spp. O presente trabalho se preocupou com o desenvolvimento de protocolos que não alteram excessivamente a prática empregada pelas empresas silviculturais. Para tanto, o trabalho foi dividido em 4 partes, sendo a primeira composta por uma revisão sobre enraizamento (item 2), visando elucidar todos os principais fatores que podem influenciar neste evento morfogênico. A partir desta revisão, se iniciaram estudos práticos com espécies e híbridos do gênero. O primeiro estudo (item 3) baseou-se na avaliação da morfofisiologia de miniestacas de três espécies de eucalipto (E. urograndis, E. benthamii e E. urophylla) em contato com AIB em pó e subsequente aplicação de tratamentos com bioestimulantes (ácido tânico e Algaren BZn&#174;) utilizados de forma isolada e/ou em associação diretamente na base das miniestacas. O segundo estudo (item 4) avaliou a atuação destes mesmos tratamentos com bioestimulantes, em microcepas de Eucalyptus urograndis em fase de alongamento in vitro das brotações e sua posterior aclimatização. Por fim, o terceiro estudo (item 5) foi baseado na utilização dos tratamentos com bioestimulantes em microestacas de E. urophylla em fase de aclimatização em miniestufas, sendo os bioestimulantes aplicados na base das microestacas e na base das miniestufas (diretamente na bandeja). Em todos os experimentos foram coletados dados referentes aos parâmetros morfofisiológicos e, observou-se no primeiro e segundo experimento, que o ácido tânico na concentração de 250mg/L, foi o melhor tratamento empregado. Já, para o terceiro experimento, o Algaren BZn&#174; na concentração de 1ml/L, apresentou resultados mais favoráveis. De acordo com as análises histológicas da rizogênese para todos os experimentos, verificou-se que as raízes adventícias desenvolvidas apresentaram origem cambial e conexão direta com o sistema vascular da parte aérea, indicando serem funcionais. O que permitiu constatar que, de forma geral, a adição de bioestimulantes otimizou a produção de mudas clonais de Eucalyptus. / According to the great importance that Eucalyptus genus presents, more studies are related to genus species propagation optimization have been conducted. Being the rooting recalcitrance that some species presents the main obstacle related to its cloning, this work had the aim to evaluate the biostimulants use in mini and microcuttings rooting process of Eucalyptus spp. For this, the present work was concerned with the protocols development that does not excessively alter the practice employed by silvicultural business. For this, the work was divided into 4 parts, the first have a rooting review (item 2), in order to elucidate all the main factors that may influence this morphogenic event. From this review, practical studies with species and hybrids of the genus were started. The first study (item 3) was based on the minicuttings morphology evaluation of the three eucalyptus species (E. urograndis, E. benthamii and E. urophylla) in contact with IBA in talc and the subsequent application of biostimulant treatments (tannic acid and Algaren BZn&#174;) used in isolation and/or in combination directly on minicuttings base. The second study (item 4) evaluated the performance of these same treatments with biostimulants in E. urograndis microcuttings on the shoots elongation stage in vitro and their subsequent acclimatization. Finally, the third study (item 5) was based on the biostimulant treatments use in E. urophylla microcuttings in acclimatization phase in ministuff. The biostimulants were applied at microcuttings base and at ministuff base (directly on the trays). In all experiments, data regarding morphophysiological parameters were collected and it was observed in the first and second experiments that tannic acid at 250mg/L concentration was the best treatment used. For the third experiment, the Algaren BZn&#174; in the concentration of 1 ml/L, presented more favorable results. According to the rhizogenesis histological analyzes for all the experiments, it was verified that the adventitious roots developed presented cambial origin and had a direct vascular connection with the aerial part, indicating its functionality. This showed that, in general, the biostimulants addition optimized the production of clonal Eucalyptus seedlings.

Page generated in 0.0542 seconds