Made available in DSpace on 2014-08-20T13:59:04Z (GMT). No. of bitstreams: 1 tese_fabiana_timm.pdf: 864202 bytes, checksum: eb076826201adf7fc6b54e9e5d185d98 (MD5) Previous issue date: 2012-07-31 / The salinity negatively affects crop productivity due to osmotic and toxic effect caused by excess Na+ and Cl- in the soil. The mechanisms used by tolerant species include the control of Na+ uptake, compartmentalization and translocation of Na+ and Cl- by membrane transporters; production of protective osmolytes, increased activity of antioxidant enzymes and cell signaling. Thus, the objective was to evaluate seed germination and early growth of nine white oat genotypes, in order to identify contrasting genotypes for salt tolerance character. For this analysis was performed on the physiological white oat genotypes under different salt concentrations (0; 25; 50; 75 and 100 mM NaCl). The variables analyzed were: germination, first counting germination, index of germination speed, shoot and root length, shoots and roots dry mass of shoots and roots seedling. Based on these results were selected contrasting genotypes in which it was determined the activity of antioxidant enzymes and content of photosynthetic pigments. Seed germination was less affected than the growth of seedlings with increasing concentrations of NaCl, and the root length was most affected. The length of roots and shoots were the variables that best discriminated contrasting genotypes, enabling the identification of a tolerant genotype (URS 22) and sensitive (UPF 16), evidenced by the activity of antioxidant enzymes. The levels of chlorophyll and carotenoid were reduced in accordance with the increase in salt concentration in both genotypes, and lower in genotype UPF 16. Based on the analysis of initial growth was possible to discriminate a sensitive genotype (UPF 16) and a tolerant (URS 22), which showed higher and lower activity of antioxidant enzymes as well as lower and higher pigment contents, respectively. / A salinidade afeta negativamente a produtividade das culturas devido ao efeito osmótico e tóxico causado pelo excesso de íons Na+ e Cl- no solo. Os mecanismos utilizados por espécies tolerantes incluem controle na absorção de Na+; compartimentalização e translocação de Na+ e Cl- pelos transportadores de membrana; produção de osmólitos protetores; aumento na atividade de enzimas antioxidantes e sinalização celular. Assim sendo, o objetivo foi avaliar a germinação das sementes e o crescimento inicial de nove genótipos de aveia branca, identificar genótipos contrastantes para o caráter tolerância à salinidade. Para isso, foram feitas análises fisiológicas dos genótipos de aveia branca submetidos a diferentes concentrações salinas (0,0; 25; 50; 75 e 100 mM de NaCl). As variáveis analisadas foram: porcentagem de germinação, primeira contagem de germinação, índice de velocidade de germinação, comprimento de parte aérea e raiz, massa seca da parte aérea e raízes das plântulas. Com base nestes resultados, foram selecionados genótipos contrastantes nos quais foi determinada a atividade de enzimas antioxidantes e o teor de pigmentos fotossintéticos. A germinação das sementes foi menos afetada que o crescimento das plântulas com o aumento das concentrações de NaCl, sendo que o comprimento de raiz foi mais prejudicado. O comprimento da raiz e parte aérea foram às variáveis que melhor discriminaram os genótipos contrastantes, possibilitando a identificação de um genótipo tolerante (URS 22) e um sensível (UPF 16), comprovado pela atividade das enzimas antioxidantes. Os teores de clorofila e carotenoides reduziram de acordo com o aumento da concentração salina em ambos os genótipos, sendo menores no genótipo UPF 16. Com base nas análises de crescimento inicial foi possível discriminar um genótipo sensível (UPF 16) e um tolerante (URS 22), os quais apresentaram maior e menor atividade das enzimas antioxidantes bem como, menor e maior conteúdo de pigmentos, respectivamente.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This thesis presents results of an experiment with crop-livestock integration in two growing seasons (2012/2013 and 2013/2014). In cold seasons was used pasture formed by the mixture of black and annual ryegrass grazed sheep on a three-factor experiment (Grazing management, nitrogen fertilization level and seed inoculation) in experimental design of randomized blocks. For Grazing management factor to pasture was managed as follows: (i) conventional grazing (PC), where the animals remained in the pasture throughout the trial without a control of the grass height, (II, III and IV) - stubble height of 10, 20 and 30 cm and a witness without grazing (SP). Nitrogen rates were three (0, 50 and 100 kg nitrogen ha-1), and seeds of oat and ryegrass inoculated or not with bacteria Azospirillum brasilense. In herbage mass of pasture collected at the entrance and exit of animals, botany separation of the components (leaf, stem, senescent material, inflorescence) was carried out and was obtained total biomass production in the different treatments. It was found that the biomass production of black and annual ryegrass increased with the application of 100 kg nitrogen ha-1 and the Azospirillum brasilense inoculation and the proportion of structural components varied according to the different grazing managements, doses nitrogen and inoculation with Azospirillum brasilense. Above straw of black and annual ryegrass were introduced corn and soybeans in no-till system, which were inoculated or not with bacteria Azospirillum brasilense. In maize, higher plant height was checked when it is grown under straw oat and ryegrass in the absence of grazing, which also favors the crop yield. In conditions of drought nitrogen applied on grassland favors the development of corn, increasing plant height, insertion height of spike and stem diameter. In maize yield this effect is pronounced in areas where it had a larger mass of waste fodder. Inoculation with Azospirillum brasilense has a positive effect on the components of income and productivity of independent corn growing season and hybrid used. The soybean crop has the best yield in crop-livestock integration system as established under black and annual ryegrass pasture managed with heights between 20 and 30 cm. Inoculation with Azospirillum brasilense should not be used alone in the soybean crop. / Este trabalho apresenta resultados de um experimento com integração lavoura-pecuária em dois anos agrícolas (2012/2013 e 2013/2014). Nas estações frias se utilizou pastagem formada pela mistura de aveia preta e azevém sob pastejo com ovinos, em um experimento trifatorial (manejo do pastejo, doses de nitrogênio e inoculação de sementes), em delineamento experimental de blocos ao acaso. Para o fator manejo do pastejo a pastagem foi manejada da seguinte forma: (I) pastejo convencional (PC), onde os animais permaneciam na pastagem por todo o período experimental sem um controle da altura da pastagem, (II, III e IV) - altura da pastagem na saída dos animais de 10, 20 e 30 cm e uma testemunha sem pastejo (SP). As doses de nitrogênio foram três (0, 50 e 100 kg de nitrogênio ha-1), e sementes de aveia preta e azevém inoculadas ou não com a bactéria Azospirillum brasilense. Na massa de forragem da pastagem coletada na entrada e saída dos animais, foi realizada a separação botânica dos componentes (folha, colmo, material senescente, inflorescência) e foi obtida a produção de biomassa total nos diferentes tratamentos. Verificou-se que a produção de biomassa da pastagem de aveia preta e azevém aumentou com a aplicação de 100 kg de nitrogênio ha-1 e com a inoculação de Azospirillum brasilense e a proporção dos componentes estruturais variaram em função dos diferentes manejos de pastejo, doses de nitrogênio e inoculação com Azospirillum brasilense. Sobre a palhada de aveia preta e azevém foram introduzidas as culturas de milho e soja em semeadura direta, as quais foram inoculadas ou não com a bactéria Azospirillum brasilense. Na cultura do milho, maior altura de plantas foi verificado quando este é cultivado sob palhada de aveia preta e azevém na ausência de pastejo, o que favorece também a produtividade da cultura. Em condições de estiagem o nitrogênio aplicado na pastagem favorece o desenvolvimento do milho, aumentando a altura da planta, altura de inserção de espiga e diâmetro de colmo. Na produtividade do milho este efeito é pronunciado nas áreas onde se tinha uma maior massa de forragem residual. A inoculação com Azospirillum brasilense tem efeito positivo sobre os componentes do rendimento e produtividade do milho independente do ano agrícola e do híbrido utilizado. A cultura da soja possui melhores produtividades em sistema de integração lavoura-pecuária quando estabelecida sob pastagem de aveia preta e azevém manejadas com alturas de pastejo entre 20 e 30 cm. A inoculação com Azospirillum brasilense não deve ser usada isoladamente na cultura da soja.

A aveia branca (Avena sativa L.) é um cereal que apresenta múltiplos propósitos. Essa espécie é muito utilizada na alimentação humana, pelo teor de proteínas de qualidade e fibras solúveis, e na alimentação animal, como forragem verde, feno, silagem e na composição da ração, este cereal é cultivado no período de estação fria do ano, seus grãos caracterizam um alimento de alta qualidade para o consumo proporcionando benefícios à saúde como redução do colesterol sérico e redução dos riscos de enfermidades cardiovasculares. Para um elevado rendimento torna-se fundamental o uso de técnicas de manejo, como doses de adubação nitrogenada que são essenciais para as espécies de gramíneas, sendo que elevadas doses de nitrogênio podem vir a favorecer o acamamento na cultura. Porém, a insuficiência deste componente pode causar a morte prematura das folhas e retardar o seu crescimento. A produtividade em potencial com maior precisão de estimativa de eficiência de determinadas cultura podem ser obtidas por meio de modelagem matemática. O acamamento é o acidente pela qual a planta perde sua posição natural vertical, inclina-se e cai sobre o solo. Consequentemente, esse fenômeno ocasiona a redução na qualidade e rendimento de grãos de aveia, em decorrência da dificuldade de translocação dos fotoassimilados, da assimilação de carboidratos e minerais e do decréscimo da fotossíntese. Somado a isso, o acamamento ainda dificulta a colheita do campo. O efeito do redutor de crescimento na planta é a inibição da síntese de giberelina, interferindo na eficiência biológica de formação deste hormônio e acúmulo de giberelinas menos ativas, que consequentemente levam a redução do alongamento celular. A partir da introdução desse produto no comércio é relevante efetuar estudos para que se definam estratégias de manejo adequadas quanto à época e a dose de aplicação do produto na aveia branca, visto que, para esta espécie, não existe recomendação do produto. Assim o objetivo desse trabalho foi modelar o comportamento de cultivares de aveia branca sobre doses de aplicação de redutor de crescimento sobre diferentes doses de nitrogênio em cobertura, na análise dos caracteres de produção de biomassa e rendimento de grãos. Além disto, determinar o ajuste de doses de redutor associados a doses de nitrogênio que promovam maximizar a produção e os reflexos no acúmulo de matéria seca total ao longo do desenvolvimento da planta, bem como, reduzir a taxa de acamamento. As equações lineares mostraram que independente dos anos analisados a tendência de redução linear de biomassa produzida com incremento da dose de redutor é observado e que a taxa diária de produção de biomassa pode ser favorecida pela modificação do ano de cultivo. No sentido de interpretação biológica na expressão do acamamento pelo efeito do redutor, as equações de regressão testadas identificaram tendência linear, independente dos anos e experimentos com a dose de nitrogênio. O incremento de N-Fertilizante traz consigo necessidade de incrementar a dose de produto redutor. Além disto, na busca de uma equação mais completa que simulasse a possibilidade de inclusão de determinada dose de redutor de crescimento variando de 0-600 ml ha-1 também foi confirmado a ligação entre as variáveis independentes MGP e ICP nos diferentes experimentos com nitrogênio. As equações com os elementos agroclimáticos em cada dose de redutor de crescimento se mostraram altamente eficientes, inclusive, a proximidade das médias obtidas das estimadas está dentro do intervalo de confiança considerado da variação da média. Além disso, a produtividade de grãos para as doses de redutor ajustadas considerando no máximo 5% de acamamento nos estudos distintos com nitrogênio, apresentado rendimento bem próximos aos previstos para as doses de redutor. O modelo de MPI-Carvalho não se mostrou eficiente na estimativa de produção de matéria seca em aveia branca, com a proposta de ajustamento, o mesmo demonstrou ser eficiente para estimativa de rendimento biológico e de grãos, quando há incremento de redutor de crescimento. / 123 f.

The aim of our research was to investigate if oat is capable of extracting cadmium to such extent that it is usable in decontaminating polluted soils. We grew oat in a hydroponic culture during 28 days in a controlled environment and a total of 30 plants were used. The nutrient solutions were contaminated with cadmium of ten different concentrations after seven days. After harvesting the plants, the roots were separated from the shoots, placed in separate containers and then turned to ashes. The cadmium content was measured three times per sample in an atomic absorption spectrometer. Our results indicate that the ability of oat to extract cadmium from a solution is linearly dependent of the cadmium concentration of the solution. We also noted that the resistivity to cadmium of oat is limited. When the concentration of accessible cadmium ions exceeded 0,06mM, a significant difference of the shoot growth appeared. The results we obtained from shoots and roots show cadmium amounts much higher in the roots than the shoots. Despite this difference there were sufficient amounts of cadmium in the shoots to call oat a hyper accumulator. This means that oat fulfills one of the criteria of a phytoextractor.

The inability to control wild oat (Avena fatua L.) in oat (Avena sativa L.) crops by chemical means limits growers to the use of cultural control methods. Delayed seeding is the most commonly used measure; however, both crop yield and quality may suffer as a result. The objectives of this research were to i) determine if western Canadian oat genotypes differ in competitive ability, ii) determine the effect of increased plant populations on oat wild oat competition, iii) determine the effect of wild oat competition on oat quality, and iv) establish whether or not oat genotype and seed size affect germination characteristics under low temperature and moisture stress. These objectives were tested using field and laboratory experiments. Morphologically diverse oat genotypes differed in their ability to both tolerate wild oat competition and interfere with wild oat growth. Although low yielding under weed-free conditions, when subject to wild oat competition CDC Bell was able to maintain yield, reduce wild oat seed production and was the most competitive of the genotypes examined. Increased plant populations achieved through higher seeding rates provide an effective means by which to enhance the competitive ability of oat genotypes resulting in reduced yield loss and wild oat seed production. With the exception of the percentage of wild oat seed in harvested oat samples, wild oat competition had minimal effect on oat quality. Differences in germination characteristics were observed among the genotypes examined. Conclusions that emerge from this research are that i) oat genotypes differ in their ability to tolerate and interfere with wild oat competition, ii) increased plant populations may provide a long-term control measure that may reduce weed seed contribution to the soil seedbank as well as enhance the competitive ability of oat, iii) wild oat competition has minimal effect on milling oat quality with the exception of percentage of wild oat seed in harvested samples and iv) that median germination time varies among oat genotypes.

The inability to control wild oat (Avena fatua L.) in oat (Avena sativa L.) crops by chemical means limits growers to the use of cultural control methods. Delayed seeding is the most commonly used measure; however, both crop yield and quality may suffer as a result. The objectives of this research were to i) determine if western Canadian oat genotypes differ in competitive ability, ii) determine the effect of increased plant populations on oat wild oat competition, iii) determine the effect of wild oat competition on oat quality, and iv) establish whether or not oat genotype and seed size affect germination characteristics under low temperature and moisture stress. These objectives were tested using field and laboratory experiments. Morphologically diverse oat genotypes differed in their ability to both tolerate wild oat competition and interfere with wild oat growth. Although low yielding under weed-free conditions, when subject to wild oat competition CDC Bell was able to maintain yield, reduce wild oat seed production and was the most competitive of the genotypes examined. Increased plant populations achieved through higher seeding rates provide an effective means by which to enhance the competitive ability of oat genotypes resulting in reduced yield loss and wild oat seed production. With the exception of the percentage of wild oat seed in harvested oat samples, wild oat competition had minimal effect on oat quality. Differences in germination characteristics were observed among the genotypes examined. Conclusions that emerge from this research are that i) oat genotypes differ in their ability to tolerate and interfere with wild oat competition, ii) increased plant populations may provide a long-term control measure that may reduce weed seed contribution to the soil seedbank as well as enhance the competitive ability of oat, iii) wild oat competition has minimal effect on milling oat quality with the exception of percentage of wild oat seed in harvested samples and iv) that median germination time varies among oat genotypes.

<p>The aim of our research was to investigate if oat is capable of extracting cadmium to such extent that it is usable in decontaminating polluted soils. We grew oat in a hydroponic culture during 28 days in a controlled environment and a total of 30 plants were used. The nutrient solutions were contaminated with cadmium of ten different concentrations after seven days. After harvesting the plants, the roots were separated from the shoots, placed in separate containers and then turned to ashes. The cadmium content was measured three times per sample in an atomic absorption spectrometer.</p><p>Our results indicate that the ability of oat to extract cadmium from a solution is linearly dependent of the cadmium concentration of the solution. We also noted that the resistivity to cadmium of oat is limited. When the concentration of accessible cadmium ions exceeded 0,06mM, a significant difference of the shoot growth appeared. The results we obtained from shoots and roots show cadmium amounts much higher in the roots than the shoots. Despite this difference there were sufficient amounts of cadmium in the shoots to call oat a hyper accumulator. This means that oat fulfills one of the criteria of a phytoextractor.</p>

This thesis research started with analysis of oat fatty acids by using three different transmethylation methods. Basic sodium methoxide was compared with traditional acidic methanol for the total fatty acid analysis, while diazomethane was used to analyze free fatty acids. Epoxy FAs were readily hydrolyzed to dihydroxy fatty acids under the acidic condition, which suggest an overestimation of hydroxyl fatty acids and underestimation of epoxy fatty acids in previous analyses. The sodium methoxide method proved more reliable to quantify the oat seed fatty acid composition. CDC Dancer oat seed analyzed here was comprised mostly of palmitic acid (PA), oleic acid (OA) and the polyunsaturated fatty acid (PUFA) linoleic acid (LA) in quantities of 23%, 32%, and 37% of total seed FA, respectively. As well, the seed contained small quantities of another PUFA, α-linolenic (ALA) and several unusual oxygenated fatty acids (UFAs), Δ15-hydroxy fatty acid (15HFA) and epoxy fatty acids in quantities of 0.85%, 0.68%, and 2.3%, respectively. This thesis further aimed to identify and assemble all FAD2-like genes from an oat Expressed-Sequence Tag (EST) database using FAD2 and FAD2-like proteins from other organisms as query sequences in order to clone all putative FAD2-like genes-of-interest (GOIs) from oat. From the contig assemblies of retrieved oat ESTs, four distinct, putative genes were identified. From the Δ12-desaturase (FAD2) queries, a putative FAD2-like (AsFAD2) gene was identified; the Δ15-desaturase (FAD3) queries revealed two putative oat FAD3-like (AsFAD3-1 and AsFAD3-2) genes, while an ω-3 desaturase (FAD7) query identified a fourth putative full-length FAD6-like coding sequence of two possible lengths, AsFADX and AsFADX+. The GOIs were then subcloned into a yeast expression vector and functionally characterized. AsFAD2a and AsFAD2b both demonstrated Δ12 desaturation on 18:1-9c substrate. AsFAD3-1 had no activity on any substrates present, while AsFAD3-2 exhibited weak Δ15-desaturation activity specifically on 18:2-9c,12c. Finally, AsFADX converted 18:1-9c to 18:2-9c,12c, while AsFADX+ had no activity. Then, a comparative analysis of transcript levels of these GOIs via quantitative real-time PCR (qRT-PCR) was performed across oat germinating seed, root, leaf, and developing seed. AsFAD2 transcript abundance was generally much higher than AsFAD3-1 and AsFAD3-2 in all tissues. AsFAD3-1 mRNA level was highest in developing seed tissue, slightly lower in leaf tissue, and lowest in root. AsFAD3-2 mRNA was highest in germinating seed, and lowest in leaf tissue. In summary, the data produced from this thesis could be used to enhance breeding efforts for establishing oat cultivars with healthier oil content.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2008. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.