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  • 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.
281

Intensified Nature

Bacha, Ryan Joseph 10 July 2003 (has links)
While art can be an intensification of perception, this nature center recognizes the presence of nature through symbiotic connotations of its primordial elements as architectural form. Deepened experiences of both nature and architecture are to be achieved through a clarified ordering of architectonic elements and their relationship to each other, nature, and humanity. / Master of Architecture
282

Jämförelse av toppskottsbetesskador på tallplantor som är obehandlade och behandlade med viltskyddsmedel i norra Dalsland / Comparison of top shot browsing damage on young pine trees untreated and treated with game repellent in northern Dalsland

Marsell, Robin, Bouakkaz Mogen, Amar January 2024 (has links)
Flera olika arter I Sverige kan ge skador på skogen på olika vis. Där hjortviltet är en stor skadegörare på framförallt yngre tallplanteringar. Varje år kommer Skogsstyrelsen ut med information om beteskadenivåerna i landet i form av en älgbetesinventeringsrapport (ÄBIN). Skogsstyrelsen uppmanar varje år till att det ska skjutas mer älg för att få ner skadenivåerna till 5 % som är det nationella målet. Betesskador på tallplantor i tidig ålder medför en tillväxtförlust och nedklassning av framtida virke vilket påverkar den ekonomiska aspekten. Av alla olika betesskador så står toppskottsbetet för ca 75 % av skadorna, där en åtgärd för att minska betesskador är att använda viltskyddsmedel på plantorna. Syften med studien var att undersöka om det var effektivt att använda viltskyddsmedel för att minska toppskottsskador på tallplantorna, samt att undersöka om mängden RASE i bestånden hade någon påverkan på skadenivåerna på tallplantorna. Studien genomfördes som ett fältexperiment där 4 bestånd på två olika geografiska platser i norra Dalsland inventerades. På varje plats så inventerades två olika bestånd av tall med medelhöjden 1-4 meter, där ett bestånd var behandlat med viltskyddsmedel och det andra inte. Skadenivåerna mättes i 2,82 m2 stora cirkelprovytor med ett provyteförband på 60 m. provytorna lades ut objektivt i ett rutnät på analoga kartor innan inventeringen. I varje provyta så mättes stamantal, andel RASE stammar och antal toppskottsskadade tallplantor.  Resultaten visade en signifikant skillnad mellan tallbestånden, där de viltskyddsbehandlade plantorna var mindre betade på båda de olika områdena i norra Dalsland. RASE plantor hittades endast på det ena området, och där var den totala skadefrekvensen högre på tallplantorna både på de behandlade och obehandlade plantorna.  En slutsats i studien är att viltskyddsmedel har god effekt för att skydda yngre tallplantor från att bli toppsskottsskadade av hjortviltet. Men också att andelen RASE plantor i tallbestånden inte verkade ha en minskad effekt på toppskottsskadorna på tallen, det såg snarare ut som att skadorna ökade när RASE andelen var högre. Det skulle eventuellt kunna innebära att fodertillgången är för låg till storleken på hjortviltstammen i landskapet.
283

Effect of salinity on germination and seedling growth of Canola (Brassica napus L.)

Bahizire, Francois B. 03 1900 (has links)
Thesis (MScAgric (Agronomy)--University of Stellenbosch, 2007. / Soil salinity is a serious constrain to crop production in many countries. In the Western Cape canola production area, large variability in soil properties within the same field is a very common feature. Some of this variability may be ascribed to differences in salinity. These saline patches affected the germination and survival of cereal crops like wheat and may therefore also be a reason for the high variability and generally low canola yields obtained in this area. It will therefore be important to quantify the effect of such saline conditions on the germination and seedling establishment of canola in an effort to improve yields. In this study several experiments were conducted under controlled conditions in either Petri dishes in an incubator or pots in a temperature controlled glasshouse to determine the salinity response of canola. Results of the experiments done in Petri dishes, showed that the germination response of canola (Brassica napus L., cv. Tornado) to increasing levels of salinity is very similar to that of wheat (Triticum aestivum L., cv SST 88). Although canola germinated more rapidly than wheat at a temperature of 20 ºC, the final percentage germination for both crops decreased severely when NaCl induced salinity exceeded levels of an EC of 8 dS m-1, but less severe responses were obtained with NaCl/CaCl2 induced salinity. Under soil conditions an interaction between soil type and salinity level showed that the responses in sandy soil to an increase in salinity from 0 to 8 iv dS m-1 were less severe than in loamy soil and especially when salinity stress was induced by NaCl. Although cultivar Spektrum showed more tolerance to saline conditions during the germination and seedling stages in pot experiments when compared to other cultivars tested, these results will have to be confirmed in field trails where grain yield and quality can be measured.
284

Early Height Growth in Douglas Fir

Ferguson, C. W., Jr. 01 1900 (has links)
No description available.
285

Mosses as mediators of climate change : implications for tree seedling establishment in the tundra

Lett, Signe January 2017 (has links)
Alpine and arctic tree line expansion depends on the establishment of tree seedlings above the current tree line, which is expected to occur with climate warming. However, tree lines often fail to respond to higher temperatures. Other environmental factors are therefore likely important for tree seedling establishment. Above the tree line, establishing seedlings encounter existing vegetation such as bryophytes, which often dominate in arctic and alpine tundra. Bryophytes modify their environment in various ways and may mediate climate change effects on establishing tree seedlings, and with that tree line expansion. The aim of this thesis was to understand if and how the environment, in particular bryophytes, mediates the impact of climate change on tree seedling establishment at the alpine and arctic tree line. This was explored by reviewing literature on tree seedling establishment at alpine and arctic tree lines globally. In addition, tree seedling survival and growth of Betula pubescens and Pinus sylvestris were assessed experimentally. Here, individuals were planted into mono-specific mats of different bryophytes species and exposed to warming and different precipitation regimes. The literature review revealed that besides from temperature, tree seedling establishment is affected by a wide range of abiotic and biotic factors including water, snow, nutrients, light, disturbance and surrounding vegetation. Furthermore the review revealed that for example vegetation can change tree seedling responses to climate change. The experiments showed that especially tree seedling survival was adversely affected by the presence of bryophytes and that the impacts of bryophytes were larger than those of the climate treatments. Seedling growth, on the other hand, was not hampered by the presence of bryophytes, which is in line with earlier findings that seedling survival, growth and seed germination do not respond similarly to changes in environmental conditions. Moreover, we found several indications that vegetation above the tree line, including bryophytes, mediated tree seedling responses to warming and precipitation or snow cover. This thesis shows that temperature alone should not be used to predict future tree seedling establishment above the alpine and arctic tree line and that extrapolations from climate envelope models could strongly over or under estimate tree line responses to warming. This underlines the value of multi-factorial studies for understanding the interplay between warming and other environmental factors and their effects on tree seedling establishment across current tree lines.
286

Mosses as mediators of climate change : implications for tree seedling establishment in the tundra

Lett, Signe January 2017 (has links)
Alpine and arctic tree line expansion depends on the establishment of tree seedlings above the current tree line, which is expected to occur with climate warming. However, tree lines often fail to respond to higher temperatures. Other environmental factors are therefore likely important for tree seedling establishment. Above the tree line, establishing seedlings encounter existing vegetation such as bryophytes, which often dominate in arctic and alpine tundra. Bryophytes modify their environment in various ways and may mediate climate change effects on establishing tree seedlings, and with that tree line expansion. The aim of this thesis was to understand if and how the environment, in particular bryophytes, mediates the impact of climate change on tree seedling establishment at the alpine and arctic tree line. This was explored by reviewing literature on tree seedling establishment at alpine and arctic tree lines globally. In addition, tree seedling survival and growth of Betula pubescens and Pinus sylvestris were assessed experimentally. Here, individuals were planted into mono-specific mats of different bryophytes species and exposed to warming and different precipitation regimes. The literature review revealed that besides from temperature, tree seedling establishment is affected by a wide range of abiotic and biotic factors including water, snow, nutrients, light, disturbance and surrounding vegetation. Furthermore the review revealed that for example vegetation can change tree seedling responses to climate change. The experiments showed that especially tree seedling survival was adversely affected by the presence of bryophytes and that the impacts of bryophytes were larger than those of the climate treatments. Seedling growth, on the other hand, was not hampered by the presence of bryophytes, which is in line with earlier findings that seedling survival, growth and seed germination do not respond similarly to changes in environmental conditions. Moreover, we found several indications that vegetation above the tree line, including bryophytes, mediated tree seedling responses to warming and precipitation or snow cover. This thesis shows that temperature alone should not be used to predict future tree seedling establishment above the alpine and arctic tree line and that extrapolations from climate envelope models could strongly over or under estimate tree line responses to warming. This underlines the value of multi-factorial studies for understanding the interplay between warming and other environmental factors and their effects on tree seedling establishment across current tree lines.
287

Tamanhos de recipientes e o uso de hidrogel no estabelecimento de mudas de espécies florestais nativas / Sizes of containers and the use of hydrogel in the establishment of native forest species seedlings

Barbosa, Tiago Cavalheiro 14 September 2011 (has links)
A demanda por projetos de restauração ecológica, com a utilização de técnicas de plantio total, tem aumentado nos últimos anos, com a consequente necessidade de otimização dos insumos para tal atividade que, além de garantir maior sobrevivência das mudas a campo, é essencial para o setor. Assim, as compensações ambientais, geradas pela obra do trecho sul do Rodoanel Mário Covas (São Paulo), proporcionaram uma importante oportunidade de se realizar alguns estudos nessa temática. O objetivo deste trabalho foi avaliar a taxa de sobrevivência e o crescimento inicial (12 meses), de 30 espécies arbóreas nativas, provenientes de mudas acondicionadas em recipientes com 3 volumes distintos (tubetão 290 cm3, tubetinho 56 cm3 e bandeja 9 cm3), com e sem utilização de hidrogel no plantio, e submetidas às mesmas ações de manutenção. As espécies nativas regionais contemplaram todos os grupos sucessionais (pioneira e não pioneiras), pertencentes a 17 famílias botânicas. Como resultados deste trabalho, pode-se concluir que as espécies provenientes do recipiente tubetão obtiveram as menores porcentagens de mortalidade, seguidas de tubetinho e bandeja, entretanto algumas espécies de bandeja mostraram-se com índices de mortalidade menores, se comparadas a outras espécies provenientes de tubetinhos, apresentando assim possibilidades de uso, desde que adotados manejos diferenciados (irrigação pós-plantio e controle de competidores) visando a garantir o aumento da sobrevivência inicial das mudas. O hidrogel não interferiu no estabelecimento e nem no crescimento das mudas nos diferentes recipientes, para o período em que o experimento foi avaliado. Quanto ao desenvolvimento das mudas em crescimento e incremento de altura, pode-se concluir que, uma vez garantido o estabelecimento das mudas, não houve diferenças entre os recipientes, reforçando que, com manejos diferenciados, os custos da restauração poderão ser significativamente reduzidos, para as situações que exijam como metodologia o plantio total na restauração ecológica de uma dada área. / The demand for ecological restorations project, using total planting techniques, has increased in recent years, with the consequent optimizations need of inputs for such activity that, besides increasing the seedlings survival in the field, is essential for the sector. Thus, environmental compensation, generated by the work of the southern section of the Rodoanel Mário Covas (São. Paulo), provided a valuable opportunity to conduct some studies in this area. This studys aim was to evaluate the survival rate and early growth (12 months) of 30 native species from plants in containers packed with three separate volumes (290 cm3 tubetão, tubetinho 56 cm3 and bandeja 9 cm3), with and without hydrogels use at planting, and subordinated to the same maintenance actions. The regional native species, contemplated at all successional groups (pioneer and non-pioneer), belonging to 17 botany families. As a result of this work, we can conclude that species from the container tubetão had the lowest percentage of mortality, followed by tubetinho and bandeja, however some bandeja species have come out with lower mortality rates, compared to other species from tubetinhos, thus presenting use opportunities since different management are adopted (irrigation after planting and control of competitors) in order to guarantee the increase of initial survival of seedlings. The hydrogel did not affect the establishment and neither the growth of seedlings in different containers, during the period in which the experiment was evaluated. Concerning the seedlings development in growth and increase in height, one can conclude that once guaranteed the seedlings establishment of, there were no differences between the containers, reinforcing that with different managements, the restoration costs may be significantly reduced for situations that require the total planting as a methodology in ecological restoration of a given area.
288

Restauração florestal e estoque de carbono em modelos de implantação de mudas sob diferentes combinações de espécies e espaçamentos / Forestry restoration and carbon stock in seedlings implantation models under different combinations of species and spacing

Bufo, Luís Vicente Brandolise 30 April 2008 (has links)
Além dos já conhecidos benefícios da conservação e restauração das florestas ciliares sobre a qualidade e quantidade de água produzida pelas microbacias hidrogáficas, atualmente apregoa-se também a essas florestas a função de sumidouro de carbono. Este trabalho desenvolvido em duas propriedades produtoras de cana-de-açúcar localizadas no Norte do Estado de São Paulo (Santa Emília, município de Ituverava e Mata Chica, Morro Agudo) tem como objetivo testar variações de modelos de restauração já existentes, baseados na implantação de mudas e categorização das espécies em dois grupos denominados grupo de preenchimento e grupo de diversidade, quanto à eficiência em cobertura de copas e estoque de carbono de cada um dos modelos testados. Foram testados seis modelos de plantio, com variações em relação à forma de distribuição dos grupos (linhas alternadas de preenchimento e diversidade, alternância de indivíduos de preenchimento e diversidade na mesma linha e distribuição aleatória de indivíduos de preenchimento e diversidade), espaçamento (3 x 2 m e 3 x 3 m), e composição de espécies do grupo de preenchimento (grupo de preenchimento geral com 19 espécies, e grupo de preenchimento restrito com 10 espécies que mais se destacam em crescimento e cobertura de copas). A eficiência da cobertura de copas de cada modelo foi avaliada por dois métodos diferentes denominado: interseção na linha e interseção em pontos. No primeiro foi medido o comprimento de copas de todos os indivíduos na linha de plantio, e a porcentagem de cobertura obtida pela soma do comprimento total das copas de todas as árvores de cada parcela, em relação ao comprimento total das linhas de plantio de cada parcela. A avaliação por interseção em pontos foi realizada utilizando-se um densitômetro vertical com o qual foi verificou-se a presença ou ausência de cobertura em 108 pontos por parcela. Para a avaliação do montante de carbono estocado aos 32 meses de idade pelos diferentes modelos de plantio foram, tomadas medidas do maior diâmetro de tronco à 1,3 m, com valor de inclusão >= 5 cm, e aplicados à duas equações alométricas para a determinação da biomassa. A cobertura pelo método da interseção na linha mostrou ser influenciada pelo espaçamento utilizado sendo os espaçamentos de 3 x 3 m menos eficientes. A forma de distribuição e a composição de espécies do grupo de preenchimento não influenciaram a cobertura de copas. O método de interseção em pontos não verificou diferença significativa na cobertura entre os modelos de plantio testados. Comparando-se os blocos experimentais, para ambas as formas de avaliação da cobertura, os blocos 1 e 2 foram superiores aos blocos 3 e 4 explicando-se isso pela maior fertilidade dos solo dos blocos 1 e 2 (Faz. Santa Emília), e pelo intenso ataque de formigas observado nos blocos 3 e 4 (Faz. Mata Chica).A biomassa acumulada não foi influenciada pelo modelo de plantio, mas pelas condições de sítio acima mencionadas, tendo os blocos 1 e 2 significativamente mais biomassa estocada que 3 e 4. / Beyond the well known benefits of riparian forests conservation and restoration over water abundance and quality, these forests have been recently credited for carbon stocking. This study was developed on two sugar cane cultivation areas located on the Northern part of São Paulo State (Santa Emília Farm, in Ituverava town and Mata Chica Farm, in Morro Agudo town) and the main objective was to evaluate variations of pre-existing restoration models, which are based on plantation of seedlings classified into fulfillment or diversity group. The evaluation regarding the efficiency of carbon storing and crown cover of each used models. Six plantation models were tested, with variations related to fulfillment or diversity group\'s distribution (alternated rows of fulfillment and diversity species, alternated fulfillment or diversity individuals within the same row and random distribution), distance between plants (3 x 2 m e 3 x 3 m) and fulfillment species composition (19 species or 10 selected species with high performance related to growth and crown cover development).The efficiency of crown cover of each model was estimated for two different methods denominated: line interception and spot interception. In the first was measured the crown\'s length of all trees in the line plants, and the percentage of cover by some of total crown\'s length of all trees in the parcel, in relation the total line\'s length of each parcel. The spot interception was realized using a vertical densitometer, to verification the presence or absence of cover in the 108 spots of parcel. For evaluating the carbon storage, by different plantation models were measured all trees with the breast heigth (1,3 m) diameter with the inclusion value >= 5 cm, and applied in two allometric equations to estimate the carbon storage. The coverage by intersection line method was influenced by the distance between plants, and the 3 x 3 m distance was less efficient. The crown coverage was not influenced by distribution way species composition of fulfillment group. Considering both coverage evaluation forms, the comparison of experimental blocks indicated that blocks 1 and 2 had higher performance than blocks 3 and 4, probably because of better soil fertility properties on blocks 1 and 2 (Santa Emilia Farm) and because of intense ants\' attack observed on blocks 3 and 4 (Mata Chica Farm). Accumulated biomass was not influenced by plantation models, but by site conditions previously discussed, which resulted on higher stored biomass for individuals on blocks 1 and 2 than those on blocks 3 and 4.
289

Utilização de técnicas de análise de imagens para avaliação da morfologia interna e do vigor de sementes de sorgo / Using image analysis techniques for evaluation of internal morphology and vigor of sorghum seeds

Javorski, Maicon 10 August 2016 (has links)
A análise de imagens com a utilização de raios X em sementes e análise computadorizada de plântulas são técnicas eficientes na avaliação da qualidade de sementes de diversas espécies, constituindo-se em métodos de rápida resposta, com metodologias de simples execução e reprodução. Assim, foi proposto com a presente pesquisa avaliar metodologias que visam relacionar a morfologia interna de sementes de sorgo com seu potencial fisiológico por meio da análise de imagens radiografadas de sementes e computadorizadas de plântulas. Para tanto, foram utilizadas sementes do híbrido 50A70, representado por dez lotes. O estudo foi realizado em duas etapas, em que a primeira consistiu no uso de imagens radiografadas para relacionar a morfologia interna das sementes e sua germinação e a segunda consistiu na avaliação do vigor das sementes por meio dos testes de primeira contagem de germinação, envelhecimento acelerado, de frio, de emergência e velocidade de emergência de plântulas em areia, emergência de plântulas em campo e o uso do sistema computadorizado de imagens de plântulas (\"Seed Vigor Image System\" - SVIS®) aos dois e três dias após a semeadura do teste de germinação, para detectar diferenças de vigor das sementes armazenadas durante quatro meses. Concluiu-se que o teste de raios X é eficiente na identificação de danos por deterioração de tecidos, danos mecânicos, danos por malformação e danos por insetos, possibilitando estabelecer a relação entre o dano observado e o prejuízo causado para a germinação. A análise computadorizada de plântulas aos três dias de idade é uma alternativa segura para detectar diferenças de vigor entre os lotes. / Image analysis techniques using X-rayed seeds and computerized analysis of seedlings are considered efficient to evaluate the seed quality of various species, with a fast response and methodologies that are easy to implement and reproduce. Thus, this research aimed to evaluated methodologies that associate the internal morphology of sorghum seeds with their physiological potential via radiographed images of seeds and image processing of seedlings. Ten seed lots of the sorghum hybrid 50A70 were used in the study. The study was conducted in two phases; the first involved the utilization of radiographed images of seeds to associate their internal morphology with germination. The second consisted evaluation of vigor using first count germination, accelerated aging, cold test, emergence and speed of emergence in sand, seedling emergence in field and computerized seedling image analysis (\"Seed Vigor Image System - SVIS®\"), the seedlings were evaluated two and three days after sowing for the germination test, in order to detect variations in the seed vigor among the lots, during four months of storage. The results allowed to conclude that the X-ray test is effective in identifying damage tissue deterioration, mechanical damage, malformation damage and insect damage, enabling to establish a relationship between the observed damage and the negative effect on germination. Computerized analysis of three-day-old seedlings consists in a feasible method to detect differences in the seed vigor among the lots.
290

Contribuição dos horizontes profundos do solo para o fornecimento de nutrientes em plantações de eucalipto / Contribution of deep horizons of the soil to nutrients supply in eucalypts plantations

Silva, Eduardo Vinicius da 06 September 2011 (has links)
No Brasil, a alta produtividade das plantações florestais tem despertado grande interesse em relação à nutrição das árvores. Diante disso, este trabalho tratou de 2 estudos sobre a absorção de nutrientes pelas árvores de Eucalyptus grandis. O primeiro avaliou o potencial de absorção de N, K e Ca pelas árvores de E. grandis (6 anos de idade - 25 m de altura média) em função da profundidade, da textura e da umidade do solo. Através de tubos de plástico, aplicou-se conjuntamente os marcadores NO3 --15N, Rb+ (análogo ao K+) e Sr2+ (análogo ao Ca2+) nas profundidades de 10, 50, 150 e 300 cm, num Latossolo vermelho textura média e num Latossolo vermelho argiloso. Utilizou-se o delineamento experimental inteiramente casualizado com 3 repetições de pares de árvores por profundidade de injeção e por tipo de solo. Após a injeção dos marcadores nas quatro profundidades, coletou-se dessas árvores folhas recém expandidas em vários períodos do verão, sendo o experimento repetido no período do inverno. O conteúdo de água foi monitorado continuamente em diferentes profundidades dos dois solos. A partir das quatro profundidades de injeção dos marcadores, a determinação das concentrações foliares de Rb, de Sr e da percentagem de átomo de 15N permitiu estimar a potencial absorção relativa (PAR) e a potencial absorção relativa específica (PARE), definida na divisão da PAR pela densidade de raízes finas em cm cm-3 (DRF), na camada de solo correspondente. O segundo, através de microeletrôdos seletivos de íons, mediu os fluxos de NH4 +, NO3 -, K+ e H+ (nmol m-2 s-1) em soluções de NH4NO3 (50 µM) e KNO3 (50 µM). Os microeletrôdos foram posicionados ao longo da raiz desde a ponta (0 cm) até 0,5; 1,0; 1,5; 2,0; 3,0; 5,0; e 8,0 cm de distância da ponta da raiz. Os fluxos foram medidos na raiz fina de 4 mudas de E. grandis que permaneceram numa solução pré-tratamento menos concentrada (50 µM) e na raiz fina de 4 mudas que permaneceram numa solução pré-tratamento mais concentrada (500 µM). No primeiro estudo, os resultados sugeriram que as raízes finas de E. grandis apresentaram um contraste entre as taxas potenciais de absorção e a profundidade, dependendo do nutriente. No segundo estudo, a tendência de maior absorção K+ e NH4 + em relação ao NO3 - pôde ter ocorrido devido às células das raízes de E. grandis serem mais permeáveis ao K+ e a forma preferencial de absorção de nitrogênio desta espécie ser o NH4 +. Os padrões distintos de absorção de NH4 +, K+ e NO3 -, desde a ponta da raiz das mudas de E. grandis até 8 cm de distância, puderam resultar das diferenças morfológicas, como: maior absorção de íons entre a zona de diferenciação e elongação celular das raízes e a zona de maturação celular (zona branca até 2 cm de distância da ponta); e diminuição da absorção na zona em que as células do córtex começaram a morrer ou já estavam mortas (zona escura entre 2 e 8 cm de distância da ponta da raiz). / The high productivity of forest plantations in Brazil has attracted great interest in relation to the nutritional aspect of trees. Therefore, this work deals with two studies on nutrient uptake by trees of Eucalyptus grandis. The first assessed the potential uptake of N, K and Ca by E. grandis trees (6 years of age 25 m mean height), in Brazil, as a function of soil depth, texture and water content. We injected NO3 --15N, Rb+ (analogue of K+) and Sr2+ (analogue of Ca2+) tracers simultaneously in a solution through plastic tubes at 10, 50, 150 and 300 cm in depth in a sandy and a clayey Ferralsol soil. A complete randomized design was set up with 3 replicates of paired trees per injection depth and soil type. Recently expanded leaves were sampled at various times after tracer injection in the summer, and the experiment was repeated in the winter. Soil water contents were continuously monitored at the different depths in the two soils. Determination of foliar Rb and Sr concentrations and 15N atom% made it possible to estimate the relative uptake potential (RUP) of tracer injections from the four soil depths and the specific relative uptake potential (SRUP), defined as RUP, per unit of fine root length density (RLD) in the corresponding soil layer. The second, in solutions of NH4NO3 (50 µM) and KNO3 (50 µM) were measured the flows of NH4 +, NO3 -, K+ and H+ (nmol m-2 s-1) through microelectrodes selective ions. Along the root, the microelectrodes were positioned at the root tip (0 cm) to 0.5, 1.0, 1.5, 2.0, 3.0, 5.0, and 8.0 cm away of the root tip. The flows were measured in fine roots of 4 E. grandis seedlings that remained in a pretreatment solution less concentrated (50 µM) and fine root of 4 seedlings that remained in pretreatment solution more concentrated (500 µM) through ion selective microelectrode. In the first study, the results suggest that the fine roots of E. grandis trees exhibit contrasting potential uptake rates with depth depending on the nutrient. In the second, the trend towards greater uptake K+ and NH4 + in relation to NO3 - may be due to the root cells of E. grandis are more permeable to K+ and to the preferred form of nitrogen absorption of this species is NH4 +. The different absorptions patterns of NH4 +, K+ and NO3 - along the roots of E. grandis seedlings from the root tip up to 8 cm away can be the result of morphological differences, such as higher absorption of ions between the zone of cell differentiation and elongation of the roots and cell maturation zone (white zone up to 2 cm away from tip), and decreased absorption in the area where the cortical cells start dying or already are dead (dark zone between 2 and 8 cm away from the root tip).

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