Chronic kidney disease (CKD), a reduction in kidney function, has reached pandemic proportions and imposes a major healthcare burden worldwide. A hallmark of CKD is the accumulation of several chemical compounds, called uremic toxins, which inflict systemic and renal-specific damage. Of the known uremic toxins, kynurenine (Kyn) is known to be particularly vasculotoxic and is implicated in several complications of CKD. Indoleamine 2,3-dioxygenase 1 (IDO), which catalyzes the first step in the metabolism of Tryptophan (Trp), regulates immune response to inflammatory cytokines in tissues. IDO plays a role in apoptosis and damage during acute kidney injury (AKI), a transient decrease in kidney function. During metabolism of Trp, IDO generates Kyn, a uremic solute, and therefore IDO may play a role in the brain and kidney damage due to accumulation of Kyn. The objective of the current study was to investigate the role and regulation of IDO in CKD pathology. Studies were performed to determine whether IDO is protective or pathologic and to find how IDO is regulated in the kidney during CKD. IDO in renopathology was examined using murine models of CKD. CKD was induced via a 0.2% adenine-supplemented diet (AD) model for 21 days. IDO regulation was examined using an Indoxyl Sulfate (IS)-specific solute model. Renal function in the IDO+/+ and IDO-/- AD mice was assessed through weekly measurement of blood urea nitrogen (BUN). H&E and Masson’s trichrome stains were used to assess percentages of glomerulosclerosis (GS) and immune infiltration (II), and combined interstitial fibrosis and tubular atrophy (IFTA) score in IDO+/+ and IDO-/- mice with and without CKD. IDO protein concentration in the kidneys of all mice with and without CKD and IDO+/+ IS mice was determined via immunoblotting. Patients with kidney disease suffer from neuropsychological disorders and neurocognitive decline. The effects of uremic solutes on the CNS was examined using immortalized human umbilical endothelial vein cells (HUVEC-TERT), in vitro. Cell proliferation and viability, in the presence of IS, were measured by BrdU and Alamar blue assays, respectively. In both IDO+/+ and IDO-/-, 21 days of AD results in significant deterioration of renal function. The average IFTA score and percentage of II in IDO-/- mice increased with AD compared to ND (p<0.05, p<0.001). IDO expression was seen sporadically in the glomeruli and walls of major vessels in the kidneys of 4d AD IDO+/+ mice, and in the tubules and vessel walls in the kidneys of 14d AD IDO+/+ mice. In IDO+/+ ND mice, endogenous IDO protein expression was undetectable at a signal intensity of 119.86 ± 268.01, whereas IDO+/+ AD mice showed a 370-fold higher level of IDO protein expression compared to IDO+/+ ND (p<0.001). IDO-/- AD IDO protein expression was 9.5-fold higher than in IDO-/- AD (p<0.05). IDO expression was found to be 58-fold higher in IDO+/+ mice with IS treatment (p<0.05). In the IS mice, non-significant trends toward decrease in cellular proliferation and viability with time were also observed (p=ns). IDO is upregulated at the protein level both in a CKD model and directly by the uremic solute, IS. IDO appears to be protective in the kidney during CKD, given the trend toward increased percentage of GS and II in IDO-/- compared to IDO+/+ mice with CKD, though there is little difference seen in total kidney IFTA. IDO upregulation is linked to increased apoptosis. Blocking uremic solute production would therefore prevent IDO protein upregulation and reduce apoptosis, alleviating renal damage during CKD.

Understanding the response of soil microbial communities to various environmental stresses is of current interest, because of their pivotal role in nutrient cycling, soil organic matter mineralization and influence on plant growth. Determining the affect of several biotic and abiotic factors on soil microbial communities is the overall objective of the study. The specific goals are to determine 1) the response of microbial communities to water deficit in soil and 2) how the presence of a rich biotic community determines the direction of microbial community development in cultures. Both goals are novel and unique contributions to understanding microbial ecology in soil. Dynamics in water potentials due to drying and rewetting of soil impose significant physiological challenges to soil microorganisms. To cope with these fluctuations, many microorganisms alter the chemistry and concentration of their cytoplasmic contents. The aim of this research is to understand how the microbial biomass and their cytoplasm change in response to water potential deficits under in situ soil conditions. To address this objective we characterized intracellular and extracellular metabolites in moist, dry and salt stressed soils. Our results provided the first direct evidence that microbial communities in soil in situ utilize sugars and sugar alcohols to cope with low water potential. While the cultivation and isolation of microorganisms is essential to completely explore their physiology and ecology, 99% of soil microbes resist growing in cultures. Presence of very unnatural conditions in the culture plates was considered as main reason for low cultivability. Thus, a culture-based study was conducted whereby microorganisms were grown in association with their native habitat with an objective of mimicking native conditions to promote the growth of previously uncultivated microorganisms. Moreover, the importance of biotic communities (microbe-microbe) and abiotic soil effects were assessed on bacterial growth. Our results strongly indicate that the presence of living microbial community in the vicinity of the target culture resulted in the cultivation of novel members of rare bacterial taxa from phyla Verrucomicrobia, Bacteroidetes, Proteobacteria, and Planctomycetes. These results emphasize the need to develop new culturing methods to tap the hidden microbial potential for emerging anthropogenic needs.

This work 1) draws insights on molten salt structure and properties directly from ab initio molecular dynamics (AIMD) simulations, 2) demonstrates the advantageous symbiosis of computational and experimental collaborations on molten salt research, and 3) simultaneously generates ab initio data sets for fitting an interatomic potential model for classical molecular dynamics (MD) simulations. This work discusses the motivations for AIMD simulations of molten salts, thermophysical properties and structural characteristics of interest, advanced methodologies for AIMD simulations, and several completed AIMD studies on molten salts. Of import are the methodological contributions of this work to AIMD simulations, primarily the radical increase in generalized gradient planewave energy cutoff used to more accurately model the electron distribution across a highly-polarizable molten salt. Cutoffs of up to 2500 Rydbergs are used in this work, but 2000 Rydbergs is found to be sufficient for most AIMD NpT modelling of molten fluorides. The equilibrium liquid density of eutectic FLiNaK as a function of temperature is found to agree with the experimental density reported by Chrenkova et al. to within 0.2%, and the equilibrium liquid density of eutectic FMgNaK is found to agree with experimental measurements reported herein to within 4%. Self-diffusion coefficients in FMgNaK are also considered, with applicability to other halide salts. Molybdenum, Cesium, iodide, nickel, hydrogen, oxide, and uranium complexation are examined. It is found that solvation strength can be qualitatively determine via AIMD simulations, and that poorly solvated solutes will minimize the surface area of interaction with the salt solution. Cesium in particular is shown to be volatile or retainable in FLiBe at 500, 650, and 800 ËšC based on complexation and validated experimentally. It is shown that the chemical potential of an anion varies between melts as influenced by the different cations present in each melt. Hence, attempts to use a common electrochemical reference reaction for different salt mixtures are at best an approximation.

No / This paper aims to establish the acid concentration of finely dispersed droplets in hydrocarbon oils. Small quantities of aqueous sulphuric acid (H2SO4) were found to be trapped within hydrocarbon shells, making them inaccessible for concentration evaluation by titration. Fourier transform infrared spectroscopy (FTIR) used in the attenuated total reflection mode (ATR; FTIR-ATR) was applied to study the reaction products of squalane, C30H62, and an API Group I base oil with various concentrations of aqueous H2SO4. The absorbance comparison usually used for estimating acid concentrations was found to fail when small quantities of acid are trapped in the reaction product. It was found that the peak shift and changes in absorbance found for various pure aqueous acid concentrations were useful to establish the remaining concentration of the trapped H2SO4. This paper fulfils the identified need to study acid dissociation-dependent peak shifts of H2SO4 to find the acid concentration of finely dispersed droplets in hydrocarbon oils.

No estudo da dinâmica de solutos num meio poroso é de suma importância o conhecimento das propriedades do meio e dos líquidos percolantes, bem como de fatores externos. Um fator externo relevante é a temperatura e, nesse sentido, objetivou-se com o presente trabalho a determinação de parâmetros de transporte dos íons potássio e nitrato para diferentes valores de temperatura em experimentos de deslocamento miscível. Os parâmetros avaliados foram o fator de retardamento (R), o coeficiente de difusão/dispersão (D) e a dispersividade (&#955;) e as temperaturas utilizadas foram a ambiente (25&#176;C a 28&#176;C), 40&#176;C e 50&#176;C. Os sais utilizados foram nitrato de potássio e cloreto de potássio, preparados em uma solução composta de 50ppm de nitrato e 2000ppm de potássio e o meio poroso um Latossolo Vermelho Amarelo, textura média. Os resultados obtidos permitiram concluir que a temperatura apresentou influência na velocidade da solução no meio poroso e no coeficiente de dispersão. / In the study of solute dynamics in porous media, it is of extreme importance the knowledge of the medium and transporting liquid properties as well as of external factors as temperature. In this sense, the objective of this work was the determination of parameters for potassium and nitrate ions under different temperatures in miscible displacement experiments, in a sandy loam Oxisol. The evaluated parameters were retardation factor (R) difusion/dispersion coefficient (D) and dispersivity (&#955;), whereas the used temperatures were the prevailing temperature (25&#176;C to 28&#176;C), 40&#176;C and 50&#176;C. The used salts were potassium nitrate and potassium chloride, prepared in a composed solution of 50 ppm of nitrate and 2000 ppm of potassium. From the results, it could be concluded that the temperature showed high influence on soil solution velocity and dispersion coefficient

No estudo da dinâmica de solutos num meio poroso é de suma importância o conhecimento das propriedades do meio e dos líquidos percolantes, bem como de fatores externos. Um fator externo relevante é a temperatura e, nesse sentido, objetivou-se com o presente trabalho a determinação de parâmetros de transporte dos íons potássio e nitrato para diferentes valores de temperatura em experimentos de deslocamento miscível. Os parâmetros avaliados foram o fator de retardamento (R), o coeficiente de difusão/dispersão (D) e a dispersividade (&#955;) e as temperaturas utilizadas foram a ambiente (25&#176;C a 28&#176;C), 40&#176;C e 50&#176;C. Os sais utilizados foram nitrato de potássio e cloreto de potássio, preparados em uma solução composta de 50ppm de nitrato e 2000ppm de potássio e o meio poroso um Latossolo Vermelho Amarelo, textura média. Os resultados obtidos permitiram concluir que a temperatura apresentou influência na velocidade da solução no meio poroso e no coeficiente de dispersão. / In the study of solute dynamics in porous media, it is of extreme importance the knowledge of the medium and transporting liquid properties as well as of external factors as temperature. In this sense, the objective of this work was the determination of parameters for potassium and nitrate ions under different temperatures in miscible displacement experiments, in a sandy loam Oxisol. The evaluated parameters were retardation factor (R) difusion/dispersion coefficient (D) and dispersivity (&#955;), whereas the used temperatures were the prevailing temperature (25&#176;C to 28&#176;C), 40&#176;C and 50&#176;C. The used salts were potassium nitrate and potassium chloride, prepared in a composed solution of 50 ppm of nitrate and 2000 ppm of potassium. From the results, it could be concluded that the temperature showed high influence on soil solution velocity and dispersion coefficient

A adubação tem o intuito de fornecer nutrientes (solutos) às plantas em quantidades requeridas no momento adequado, visando obter produções agrícolas economicamente viáveis. Todavia, em alguns casos, o manejo da adubação não é feito de maneira correta, principalmente por se utilizar quantidades excessivas desses nutrientes. Juntando-se a esse fato, a água da irrigação e/ou da chuva, pode vir a ser um facilitador do escoamento superficial e da lixiviação através do perfil de solo, tornando-se, dessa forma, indisponível às plantas e, podem provocar a poluição de águas superficiais através da erosão hídrica e eutrofização, além da contaminação de águas subterrâneas e a acidificação de camadas do solo. Portanto, para evitar esses impactos ambientais, é necessário conhecer e entender a dinâmica de solutos no perfil de solo mediante a obtenção de informações que venham a caracterizar esses processos. Dentro dessas informações, tem-se a obtenção dos parâmetros de transporte de solutos. Tais parâmetros podem sofrer várias interferências do meio poroso, dentre elas a composição físico-química e mineralógica dos solos, a qual poderá determinar a capacidade de retenção ou dispersão desses íons. Dessa forma, o objetivo dessa pesquisa foi avaliar o efeito da composição físico-química e mineralógica de alguns tipos de solo sobre a dinâmica dos íons nitrato, fósforo e potássio, mediante a análise de seus parâmetros de transporte, obtidos pelo ajuste numérico das curvas de distribuição de efluentes (Breakthrough Curves, BTC) aplicando o código CFITIM dentro do software STANMOD (STudio of ANalytical MODels). Além disso, utilizando-se colunas com diferentes alturas (10 e 20 cm) e buscou-se recomendar qual altura de coluna possui acurácia sobre os parâmetros mediante simulações numéricas das BTC\'s pelo modelo HYDRUS-1D. A pesquisa foi conduzida junto ao Departamento de Engenharia de Biossistemas da Universidade de São Paulo (USP/ESALQ). Os tratamentos foram distribuídos em um esquema fatorial de 5 x 2, ou seja, cinco tipos de solo e duas alturas de colunas de solo para cada íon, individualmente. O delineamento experimental foi em blocos casualizados, com três blocos, totalizando 30 parcelas por soluto. Para a análise dos resultados, os parâmetros de transportes foram submetidos à análise de variância e a avaliação do desempenho do modelo pelos índices estatísticos: Raiz do Erro Quadrático Médio (RMSE), Erro Absoluto Médio (MAE) e o Coeficiente de Determinação (R2). Diante dos resultados obtidos, o solo PV foi diferente estatisticamente dos demais solos em todos os íons no coeficiente de dispersão. Diante das diferentes nas alturas das colunas, os solos PV, PVAe, NV e PVAd apresentaram diferenças significativas no fator de retardamento e os coeficientes de distribuição e dispersão nos íons nitrato e potássio. Sendo assim, recomendou-se a altura de 20 cm, pois os parâmetros determinados foram precisos em relação a 10 cm, pelo fato do modelo HYDRUS-1D ter alcançado um desempenho adequado nas simulações das BTC\'s nos solos arenosos e argilosos. / Fertilizer is applied to provide nutrients (solutes) for plants in required quantities, and at the right time, to facilitate economically viable agricultural production. However, in some cases excessive quantities of fertilizers are applied. Such overapplication can result in runoff and ions leaching through the soil profile, where they are unavailable to plants, and can cause surface water pollution by water erosion and eutrophication, besides of groundwater contamination and soil acidification. To avoid these environmental impacts, it is necessary to characterize the transport parameters that govern the dynamic of solutes in soil profile. These parameters are influenced by porous media properties, such as mineralogical composition of soils, that regulate the retention or dispersion of ions. The objective of this study was to evaluate the effect of physicochemical and mineralogical composition of soils on transport parameters of nitrate, phosphorus, and potassium, estimated by using the CFITIM code inside of STANMOD (STudio of ANalytical MODels) software to fit BTC\'s. Besides that, using of columns with different heights (10 and 20 cm) and recommended the columns height with accuracy under transport parameters by numerical simulations of the BTC\'s using the HYDRUS-1D model. The research was conducted in the Department of Biosystems Engineering, University of São Paulo (USP/ESALQ). The treatments were a 5 x 2 factorial with five soils and two column heights for each individual solute. The experimental design was random blocks, with three blocks, totaling 30 plots for each solute. For analysis of results, the transport parameters were submitted a variance analysis and the evaluation of model performance by statistical indexes: Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Determination Coefficient (R2). The dispersion coefficient for PV soil were significantly different from those for other soils, for all ions. In front of the different heights of the columns, PV, PVAe, NV and PVAd soils showed significant differences in retardation factor, and distribution and dispersion coefficients, for nitrate and potassium ions. The parameters obtained from 20 cm columns were accurate than those obtained from 10 cm height, based on adequate performance of HYDRUS-1D model in BTC\'s simulations of sandy and clay soils.

Thesis (M.S.); Submitted to Iowa State Univ., Ames, IA (US); 12 Dec 2003. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2608" Maria Ambert Sanchez. 12/12/2003. Report is also available in paper and microfiche from NTIS.

FEIJÃO, Alexcyane Rodrigues. Crescimento, trocas gasosas, partição de íons e metabolismo do nitrogênio em plantas de milho submetidas à salinidade e diferentes fontes de N. 2009. 111 f. Dissertação (Mestrado em Bioquímica) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2009. / Submitted by JOANA BEZERRA (joanabib@yahoo.com.br) on 2012-12-07T21:46:44Z No. of bitstreams: 1 2009_dis_arfeijao.pdf: 674672 bytes, checksum: 5d66d02c1147abcb46edeb17e2f22ddb (MD5) / Approved for entry into archive by Érica Barros(ericabarros@ufc.br) on 2012-12-11T21:13:25Z (GMT) No. of bitstreams: 1 2009_dis_arfeijao.pdf: 674672 bytes, checksum: 5d66d02c1147abcb46edeb17e2f22ddb (MD5) / Made available in DSpace on 2012-12-11T21:13:25Z (GMT). No. of bitstreams: 1 2009_dis_arfeijao.pdf: 674672 bytes, checksum: 5d66d02c1147abcb46edeb17e2f22ddb (MD5) / This work aimed to study the effect of N source in the growing, gas exchanges, ion partitions and N metabolism in maize plants (Zea mays L.) submitted to salinity. For this, maize seeds were sown in plastic cups with vermiculite and maintained in greenhouse. After that, the seedlings were transferred to a hydroponics culture with N concentration of 6 mM, in the forms of NO3-, NO3-/NH4+ or NH4+. After five days in these conditions, we started the addition of NaCl, which was gradually increased each day by 25 mM until it reaches a final concentration of 100 mM. The harvests were carried out 4, 11 and 18 days after the beginning of the salt treatment. In control conditions, the plants fed with the mixed NO3-/NH4+ were the ones which presented the greatest shoot growth, compared to other N treatments. There was a great growth reduction when the plants were submitted to salinity, but this effect was not influenced by the N source used. Generally, the salinity reduced the stomatal conductance (gs), transpiration (E), photosynthesis (A) and the relation between the intercellular and outercellular CO2 concentration (Ci/Co ) in plants of all N treatments and in different times of harvest. However, in plants fed with NH4+ and after 18 day of salt treatment a great reduction in the gs, A and E and an increase in the Ci/Co ratio were observed. The Na+ contents increased with salinity, despite that, in plants fed with NH4+, these contents were lower than in the other N treatments in salinity conditions. The K+ contents, on the other hand, were reduced by salinity, and the plants fed with the mixed NO3-/ NH4+ and only NH4+ absorbed less K+ than the ones fed only with NO3-, mainly in the leaves and stems of plants after 11 days and in leaves and roots of plants after 18 days of salt stress. This way, there was influence of N source in the Na+/K+ ratio, particularly in roots of plants after 18 days of exposure to salt stress, whose lower increases in this parameter were observed in the plants treated only with NO3-. The greatest increments in the Cl- contents caused by salinity were observed in plants fed with NO3- and with the mixed NO3-/ NH4+. However, in control conditions, these contents were increased in leaves and stems of plants fed only with NH4+. The NO3- contents were higher in plants fed with NO3- and NO3-/NH4+, when compared to the ones fed only with NH4+, both in control and salinity conditions. The greatest and lowest Cl-/NO3- ratio were found, respectively, in plants treated with NO3- and with NH4+. The shoot NH4+ contents were little influenced by salinity or by N source, however, in roots of plants fed with NH4+ and under salinity, there was a great accumulation of these ions after 18 days of stress. The soluble carbohydrates contents, in general, increased by salinity, except in the leaves and stems (after 18 days of salt stress) and in the roots (during all the experimental period) of the plants treated with NH4+. Generally, the soluble proteins and soluble amino acids contents were increased by salinity, and the biggest quantities of these solutes were observed in the roots of plants fed with NH4+ and after 18 days of salt stress. The total N contents were reduced by salinity and it was observed especially in plants fed only with NO3-. In the leaves, the activities of nitrate reductase (NR) and nitrite reductase (NiR) were greater in plants fed with NO3- and with the mixed NO3-/ NH4+. Little influence of salinity in NiR activity was observed in maize leaves. In the leaves, the salinity influenced differently the activity of glutamine synthetase (GS) between the different sources of N and time of salt exposure. However, in the roots, in general, the GS activity increased withy salinity, except for the plants fed with NH4+, which were not influenced by this stress. After 18 days of salt exposure, the GS activity was greater in the plants fed with NH4+, compared to the other N treatments. The activity of glutamate synthase (GOGAT), in the leaves, in generral, increased with salinity, despite that, this activity was reduced in the roots mainly in the plants fed with NO3-, after 4 days, and with NH4+, after 11 and 18 days. These results suggest that the several N sources did not influence the tolerance of maize plants to salinity. However, the plants fed with NO3- had better results in ion relations. And greatest GS activities observed in roots of the plants fed with NH4+, after 18 days of stress, helped in the osmotic adjustment, as a consequence of the accumulation of soluble proteins and soluble amino acids / O objetivo deste trabalho foi estudar o efeito da fonte de N no crescimento, nas trocas gasosas, na partição de íons e no metabolismo do N em plantas de milho (Zea mays L.) submetidas à salinidade. Para isto, sementes de milho foram semeadas em copos plásticos contendo vermiculita, sendo mantidas em casa de vegetação. Em seguida, as plântulas foram transferidas para um meio hidropônico com concentração de N igual a 6 mM, nas formas de NO3-, NO3-/NH4+ ou NH4+. Após cinco dias nestas condições, iniciou-se a adição de NaCl, que foi feita em parcelas de 25 mM por dia, até atingir a concentração final de 100 mM. As coletas foram realizadas aos 4, 11 e 18 dias após o início do tratamento salino. Em condições controle, as plantas nutridas com a mistura NO3-/NH4+ foram as que apresentaram o maior crescimento da parte aérea, em comparação aos demais tratamentos de N. Houve uma forte redução do crescimento quando as plantas foram submetidas à salinidade, mas este efeito foi independente da fonte de N empregada. De maneira geral, a salinidade reduziu a condutância estomática (gs), a transpiração (E), a fotossíntese (A) e a relação entre a concentração interna e externa de CO2 (Ci/Co) das plantas de todos os tratamentos de N e nos diferentes tempos de coleta. Entretanto, nas plantas cultivadas com NH4+ e aos 18 dias do tratamento salino, foram observados uma redução acentuada na gs, A e E e um aumento na relação Ci/Co. Os teores de Na+ aumentaram com a salinidade, contudo, nas plantas nutridas com NH4+, esses teores foram menores do que os dos demais tratamentos de N em condições de salinidade. Os teores de K+, por sua vez, foram reduzidos pela salinidade, sendo que as plantas nutridas com a mistura NO3-/ NH4+ e apenas NH4+ absorveram menos K+ do que as cultivadas apenas com NO3-, principalmente nas folhas e colmos das plantas aos 11 dias e nas folhas e raízes das plantas aos 18 dias de estresse salino. Dessa forma, houve influência da fonte de N na relação Na+/K+, particularmente nas raízes das plantas aos 18 dias de exposição ao estresse salino, cujos menores aumentos nesse parâmetro foram observados nas plantas tratadas apenas com NO3-. Os maiores incrementos nos teores de Cl- causados pela salinidade foram observados nas plantas cultivadas com NO3- e com a mistura NO3-/ NH4+. Porém, em condições controle, esses teores foram aumentados nas folhas e colmos das plantas cultivadas apenas com NH4+. Os teores de NO3- foram maiores nas plantas nutridas com NO3- e NO3-/NH4+, quando comparadas às nutridas somente com NH4+, tanto em condições controle quanto de salinidade. A maior e a menor relação Cl-/NO3- foram encontradas, respectivamente, nas plantas tratadas com NO3- e com NH4+. Os teores de NH4+ da parte aérea foram pouco influenciados pela salinidade ou pela fonte de N, porém, nas raízes das plantas nutridas com NH4+ e sob salinidade, houve um grande acúmulo desses íons aos 18 dias de estresse. Os teores de carboidratos solúveis foram, em geral, aumentados pela salinidade, com exceção nas folhas e colmos (aos 18 dias de estresse salino) e nas raízes (durante todo o período experimental) das plantas tratadas com NH4+. De maneira geral, os teores de proteínas solúveis e de N-aminossolúveis foram aumentados pela salinidade, sendo que as maiores quantidades destes solutos foram observadas nas raízes das plantas tratadas com NH4+ e aos 18 dias de estresse salino. Os teores de N-total foram reduzidos pela salinidade, sendo isto observado especialmente nas plantas nutridas apenas com NO3-. Nas folhas, as atividades da redutase do nitrato (NR) e da redutase do nitrito (NiR) foram maiores nas plantas tratadas com NO3- e com a mistura NO3-/ NH4+. Foi observada pouca influência da salinidade na atividade da NiR das folhas de milho. Nas folhas, a salinidade influenciou diferentemente a atividade da sintetase da glutamina (GS) entre as diferentes fontes de N e tempos de exposição à salinidade. Porém, nas raízes, de maneira geral, a atividade da GS aumentou com a salinidade, com exceção das plantas tratadas com NH4+, que não foram influenciadas por este estresse. Aos 18 dias de exposição à salinidade, a atividade da GS foi maior nas plantas tratadas com NH4+, em comparação com os demais tratamentos de N. A atividade da sintase do glutamato (GOGAT), nas folhas, em geral, aumentou com a salinidade, contudo, nas raízes essa atividade foi reduzida principalmente nas plantas cultivadas com NO3-, aos 4 dias, e com NH4+, aos 11 e 18 dias. Esses resultados sugerem que as diversas fontes de N não influenciaram na tolerância das plantas de milho à salinidade, entretanto as plantas nutridas com NO3- foram melhores nas relações iônicas e as maiores atividades da GS observadas nas raízes das plantas cultivadas com NH4+, aos 18 dias de estresse, ajudaram no ajustamento osmótico, como conseqüência do acúmulo de proteínas solúveis e N-aminossolúveis

Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-28Bitstream added on 2014-06-13T21:06:43Z : No. of bitstreams: 1 carlin_sd_dr_jabo.pdf: 560339 bytes, checksum: 8b2e1669f83b62325f0519f3baf373d4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / No presente trabalho foi verificado o ajuste osmótico no crescimento inicial de cana-de-açúcar, cv. IAC91-5155, sob efeito da interação dos estresses hídrico e ácido no solo. Para tanto, foram quantificados os teores de três solutos compatíveis, prolina, glicina betaína e trealose. Também foi estudada a atividade da nitrato redutase e os teores de clorofilas. O estudo de todas estas variáveis teve por objetivo propor a utilização destes compostos como indicadores fisiológicos de aclimatação da cana-deaçúcar sob efeito da interação de ambos os estresses. O experimento foi realizado em casa de vegetação com 29,7±4,3oC e 75±10 UR%. Foram utilizados três tratamentos de disponibilidade hídrica (capacidade de campo, CC): controle (70%), estresse moderado (55%) e estresse severo (40%) e três tratamentos de acidez no solo (saturação por bases, V%): controle (55%), média acidez (33%) e alta acidez (23%). O delineamento experimental utilizado foi o de blocos casualizados em esquema fatorial 3x3, com quatro repetições. Após 60 dias sob estresses foram determinados os teores dos solutos compatíveis, a atividade da nitrato redutase e os teores das clorofilas. Os resultados mostram que houve acúmulo dos três solutos compatíveis evidenciando que ocorreu ajuste osmótico. Prolina e glicina betaína são indicadores fisiológicos do efeito da interação de ambos os estresses enquanto trealose é indicadora apenas para o estresse hídrico. Também, a atividade da nitrato redutase pode ser utilizada como indicador do estresse hídrico e os teores das clorofilas a, b e total para os estresses hídrico ou ácido. A massa de matéria seca da parte aérea, o número de folhas e a área foliar das plantas jovens de cana-de-açúcar, ajustadas osmoticamente, são reduzidos pelos estresses. Os efeitos interativos de ambos... / In this present work was verified the osmotic adjustment in the initial plant growth sugarcane cv. IAC91-5155 under interaction effect of water and acid stress in the soil. For this, were quantified three compatible solutes content, as follows: proline, glycine betaine and trehalose. It was verified also the nitrate reductase activity as well the chlorophyll content. The study of all parameters aimed to propose the use components as physiological indicators to acclimation of sugarcane plants under interaction the both stress. The experiment was carried out in a greenhouse under 29.7±4.3oC and 75±10%. Three water availability treatments (Field Capacity – FC%): control (70%), moderate stress (55%), and extreme stress (40%) and three soil acidification treatment (Base Saturation – BS%): control (55%), average acidity (33%), and high acidity (23%) were used. The experimental design used was the randomized blocks in a 3x3 factorial scheme and four replicates. After sixty days under stress were determined compatible solutes, nitrate reductase and chlorophyll content. Our results showed that there was the accumulation of three compatible solutes exhibiting osmotic adjustment. Glycine betaine and proline are both physiologic indicators of stresses interaction effect whereas trehalose indicates only water stress. The nitrate reductase activity can be used as water stress indicator and chlorophylls a, b and total are indicators to water or acid stress. The dry mass of shoot part, leaves number and leaf area are significantly reduced by stress in young sugarcane plants adjusted osmotically. The interaction of stresses cause decrease of dry mass while water stress reduces leaves number and leaf area.