Bibliography: leaves 183-202

Typescript (photocopy) / xxiv, 254 leaves, [71] leaves of plates : ill. ; 30 cm / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agricultural Biochemistry, 1982

Thesis (M.Ag.Sci. 1980) from the Department of Soil Science, University of Adelaide.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Agricultural Biochemistry, 1982. / Typescript (photocopy).

Thesis (Ph.D.) -- University of Adelaide, Dept. of Agronomy, 1980. / Typescript (photocopy).

In this project the effect of viral infection on the metabolism of nitrogenous compounds in tobacco plants (Nicotiana tabacum L. cv. Petit Havana SR1) was studied. The tobacco plants were infected with Potato virus Y, strain NTN, ELISA confirmed the presence of the virus. Enzymes that participate in C4 plants in Hatch-Slack cycle fosfoenolpyruvate carboxylase (EC 4.1.1.31, PEPC), NADP-dependent malic enzyme (EC 1.1.1.40, NADP-ME), pyruvate, phosphate dikinase (EC 2.7.9.1, PPDK) are present also in C3 plants and are related to plant responses to stress conditions. As a result of viral infection, the activities of all these enzymes were increased. Infection caused by PVYNTN decreased activity of nitrate reductase (EC 1.7.1.1, NR), an enzyme catalyzing reduction of nitrates to nitrites. The activity of enzymes catalyzing the synthesis of glutamine from glutamate and ammonium ions: glutamine synthetase (EC 6.3.2.1, GS) and glutamate synthase (EC 1.4.1.14, GOGAT) was enhanced. In addition to this main route of nitrogen fixation the plant can still use glutamate dehydrogenase (EC 1.4.1.2, GDH). This enzyme can also catalyze the opposite reaction, deamination of glutamate. The direction of response depends on environmental conditions. In this case a significant increase of oxidative-deaminating activity...

A folha é o principal órgão de absorção e assimilação de nutrientes dos membros epífitos com tanque da família Bromeliaceae. Pouco se conhece sobre a nutrição dessas bromélias, entretanto algumas evidências (TAKAHASHI, 2007) indicaram a possibilidade de haver uma absorção preferencial do nitrogênio na porção basal e a assimilação desse nutriente na porção apical foliar. Para se compreender melhor os mecanismos de assimilação do nitrogênio utilizados pelas bromélias epífitas com tanque, foi proposto neste trabalho dois principais objetivos: 1) verificar possíveis diferenças quanto à capacidade de assimilação do nitrogênio em diferentes porções foliares de uma bromélia epífita com tanque; 2) constatar possível preferência em assimilar fonte nitrogenada orgânica ou inorgânica, quando ambas estão disponíveis no interior do tanque. A estratégia utilizada para o primeiro objetivo foi cultivar bromélias da espécie Vriesea gigantea, cultivadas em casa de vegetação e registrar em suas folhas as variações temporais das atividades enzimáticas da urease, redutase do nitrato (NR), sintetase da glutamina (GS), desidrogenase do glutamato dependente de NADH (GDH-NADH) e arginase após o fornecimento, no interior do tanque das bromélias, de uma solução nutritiva contendo NO3-/NH4+ (3:2) ou uréia (5mM de N total), como fontes de nitrogênio. Foram analisadas as atividades enzimáticas nas porções apical e basal foliar de Vriesea gigantea nos seguintes tempos: 0, 1, 3, 6, 9, 12, 24, 48, 51, 54, 57, 60 e 73 horas após a rega. Além disso, também foram quantificadas as concentrações do amônio e da uréia endógenos presentes nos tecidos foliares de ambas as porções. Os resultados mostraram que, independente do tratamento, as atividades de GS, GDH e arginase foram mais altas na porção apical em todos os tempos de coleta. Já as atividades da NR e urease, foram crescentes e mais intensas na porção basal, da mesma forma como foi visto para as concentrações endógenas de amônio durante as primeiras 24 horas. As maiores concentrações de uréia endógenas também foram registradas principalmente na porção basal foliar. Esses resultados permitem inferir que a região apical pode estar envolvida, preferencialmente, com a assimilação do nitrogênio, enquanto que a basal, com a sua absorção, redução do nitrato e hidrólise da uréia. Além disso, sugere-se também que ocorra o transporte de amônio da base para a região de sua assimilação em aminoácidos (ápice) através do xilema e apoplasto. Em relação ao segundo objetivo, a estratégia utilizada foi fornecer à bromélia Vriesea gigantea com uma solução nutritiva que continha 5mM de nitrogênio total, disponível na forma inorgânica + orgânica (NH4+/NO3- + uréia nas proporções 1:1 ou 1:3, respectivamente). Como controle foram empregados os seguintes tratamentos: ausência de nitrogênio e presença de somente fontes inorgânicas (5mM de nitrogênio total). As porções apical e basal das folhas foram coletadas 9 horas após o fornecimento das soluções nutritivas e, posteriormente, utilizadas nas análises enzimáticas referentes às atividades da urease, NR, GS, e GDH-NADH. Além disso, foram quantificados em ambas as porções os teores endógenos de amônio, uréia, amido, açúcares totais e clorofila total. Também foram determinados as densidades de tricomas e estômatos nas duas regiões foliares. Verificou-se que as maiores atividades da GS (porção apical) e GDH (porção basal) foram registradas nos dois tratamentos com uréia (1:1 e 1:3) quando comparadas com as dos dois controles. As maiores concentrações de amônio endógeno na porção basal também foram detectadas nos mesmos tratamentos com uréia (1:1 e 1:3). Já a atividade da NR apresentou os maiores valores nos tratamentos de proporção 1:1 e no controle 2 (com somente fontes inorgânicas) na porção basal foliar. De modo interessante, a GS não mostrou o mesmo desempenho nos dois tratamentos (1:1 e controle 2), sendo que, no tratamento de proporção 1:1, a atividade foi o dobro daquela registrada no controle 2. Todos esses resultados analisados em conjunto permitem inferir que a bromélia Vriesea gigantea pode ter preferência por assimilar o nitrogênio proveniente da uréia quando essa fonte se encontra disponível no interior do tanque, mesmo quando também há a presença de formas inorgânicas (nitrato e amônio). / The leaf is considered the most important vegetative organ of tank epiphytic bromeliads due to its ability to absorb and assimilate nutrients. Little is known about the nutrition of these bromeliads, but there are evidences that the basal region of the leaf may be preferentially involved with the absorption of nutrients, whereas the apical region may be involved with its assimilation (TAKAHASHI, 2007). In order to better understand the mechanisms utilized by these tank epiphytic bromeliads to optimize the nitrogen acquisition and assimilation, it was proposed in this study two main objectives: 1) verify the existence of a differential capacity to assimilate nitrogen in different leaf portions of a tank epiphytic bromeliad; 2) analyze the nitrogen assimilation preference between inorganic and organic nitrogen sources when both are available in the tank water. The experiments of the first objective were conducted using Vriesea gigantea plants, a typical specie of tank epiphytic bromeliad, cultivated in greenhouse. Nutrient solution containing NO3-/NH4+ (3:2) or urea as nitrogen source (5mM of total N) was supplied into the tank of these plants and the activities of urease, nitrate reductase (NR), glutamine synthetase (GS), NADH-dependent glutamate dehydrogenase (GDH-NADH) and arginase were quantified in apical and basal leaf portions after 0, 1, 3, 6, 9, 12, 24, 48, 51, 54, 57, 60 and 73 hours. The ammonium and urea present in the tissues were also analyzed. Independent of the nitrogen source utilized, GS, GDH and arginase activities were higher in the apical portions of leaves in all the period analyzed. On the other hand, the opposite was observed in relation to NR and urease activities. The highest activities were detected in the basal portion of leaves at all harvest times, with increasing values during the first 24 hours of experiment. Interestingly, this same pattern was also observed in relation to the endogenous ammonium and urea: the highest contents were detected in the basal portion of leaves, with a gradual increase of ammonium in the first 24 hours of analysis. These results suggest that the basal portion of leaves was preferentially involved in nitrogen uptake, nitrate reduction and urea hydrolysis, while the apical portion was the main responsible for nitrogen assimilation. Moreover, it was possible to infer that the ammonium may be transported from the base (uptake region) to the apex of the leaves (the main nitrogen assimilation region) through the xylem and apoplast. In order to analyze the nitrogen assimilation preference of Vriesea gigantea, a nutrient solution containing 5mM of nitrogen containing a mixture of inorganic and organic sources (NH4+/NO3- + urea in the proportion 1:1 or 1:3, respectively) were supplied into the tank of the bromeliads. As a control, a nutrient solution containing no nitrogen source (control 1) or 5mM of inorganic nitrogen sources (control 2) were used. The basal and apical leaf tissues were collected after 9 hours and the activities of urease, NR, GS and GDH-NADH were analyzed. Endogenous ammonium, urea, starch, total soluble carbohydrates and total chlorophyll were also quantified. Furthermore, the density of trichomes and stomata were also analyzed on the abaxial leaf surface of both regions. The highest activities of GS (apex) and GDH (base), as well as the endogenous ammonium content (base), were registered in both treatments with urea (1:1 and 1:3) in comparison with both controls. A different pattern was obtained analyzing NR: the highest activities were observed in plants that received nutrient solutions containing only inorganic nitrogen (control 2) or a mixture of inorganic and organic nitrogen in the proportion 1:1. Moreover, an interesting behavior was observed in relation to the GS activity: it was detected the double activity of this enzyme when Vriesea gigantea was in contact with a mixture of inorganic and organic nitrogen (1:1) in comparison to the plants in the presence of only inorganic nitrogen sources. All results suggest that Vriesea gigantea may have preference to assimilate organic nitrogen source (urea), when the inorganic nitrogen sources (ammonium and nitrate) are also available in the tank water.

Wong Lee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 152-169). / Abstracts in English and Chinese. / Thesis Committee --- p.i / Abstract --- p.ii / 摘要 --- p.iv / Acknowledgements --- p.v / Abbreviations --- p.vi / List of Figures --- p.vii / List of Tables --- p.ix / Table of Contents --- p.xi / Chapter 1 --- Literature Review --- p.1 / Chapter 1.1 --- GS-GOGAT cycle in plants and bacteria --- p.2 / Chapter 1.2 --- Roles of PII in regulation of glutamine synthetase in E. coli --- p.4 / Chapter 1.2.1 --- Regulation of GS in E. col --- p.4 / Chapter 1.2.2 --- Transcriptional regulation --- p.5 / Chapter 1.2.2.1 --- The glnALG operon / Chapter 1.2.2.2 --- Intracellular signal through PII and Utase-UR / Chapter 1.2.2.3 --- NRI/NRII as two-component system / Chapter 1.2.3 --- Post-translational regulation by adenylylation and deadenylylation --- p.11 / Chapter 1.2.3.1 --- Role of PII in adenylylation/deadenylylation / Chapter 1.2.4 --- Cumulative Feedback Inhibition --- p.15 / Chapter 1.3 --- PII in other bacteria --- p.15 / Chapter 1.4 --- PII in other higher organisms --- p.20 / Chapter 1.5 --- "PII protein is conserved in enteric bacteria, cyanobacteria, archaea, algae and higher plants" --- p.23 / Chapter 1.6 --- Nitrogen assimilation in higher plants --- p.25 / Chapter 1.6.1 --- Nitrogen uptake --- p.25 / Chapter 1.6.2 --- Primary nitrogen assimilation --- p.28 / Chapter 1.6.3 --- Nitrogen transport and interconversions --- p.28 / Chapter 1.6.4 --- Nitrogen flow --- p.29 / Chapter 1.6.5 --- Molecular regulation of nitrogen assimilation and possible roles of PII in plants --- p.30 / Chapter 1.7 --- Hypothesis of this study --- p.33 / Chapter 2. --- Materials and Methods --- p.35 / Chapter 2.1 --- Materials --- p.35 / Chapter 2.1.1 --- Plant materials --- p.35 / Chapter 2.1.2 --- Equipment and facilities used --- p.35 / Chapter 2.1.3 --- Growth media --- p.37 / Chapter 2.1.4 --- Buffers and solutions used in RNA extraction --- p.38 / Chapter 2.1.5 --- Buffers and solutions used in Northern blot analysis --- p.41 / Chapter 2.1.6 --- Molecular reagents and synthetic oligonucleotides used in the preparation of DIG-labeled probes --- p.45 / Chapter 2.1.7 --- Chemicals used in BioRad Protein Assay --- p.48 / Chapter 2.1.8 --- Chemicals and apparatus used in chlorophylls extraction and quantitation --- p.49 / Chapter 2.1.9 --- Buffers and solutions used in the glutamine synthetase enzyme extraction and assay --- p.49 / Chapter 2.2 --- Methods --- p.50 / Chapter 2.2.1 --- Plant growth --- p.50 / Chapter 2.2.2 --- RNA extraction --- p.52 / Chapter 2.2.3 --- Northern blot analysis --- p.54 / Chapter 2.2.4 --- Chlorophyll extraction and quantitation --- p.61 / Chapter 2.2.5 --- Root length measurement --- p.61 / Chapter 2.2.6 --- Total glutamine synthetase enzyme assay --- p.61 / Chapter 2.2.7 --- Measurement of total nitrogen in seeds --- p.64 / Chapter 2.2.8 --- Recording growth and development --- p.64 / Chapter 3. --- Results --- p.65 / Chapter 3.1 --- Overexpression ofPII and truncated PII mRNA in transgenic plants --- p.65 / Chapter 3.2 --- General growth characteristics of PII transgenic plants when grown on soil --- p.70 / Chapter 3.3 --- Physiological changes in the PII and truncated PII transgenic lines --- p.72 / Chapter 3.3.1 --- Fresh weight of the young seedlings --- p.73 / Chapter 3.3.2 --- Chlorophyll contents of shoots --- p.75 / Chapter 3.3.3 --- Root lengths --- p.88 / Chapter 3.3.4 --- Carbon and nitrogen status of seeds --- p.94 / Chapter 3.4 --- Expression of nitrogen assimilatory genes in PII and truncated PII transgenic lines --- p.96 / Chapter 3.4.1 --- Nitrate reductases --- p.96 / Chapter 3.4.2 --- Glutamine synthetases --- p.99 / Chapter 3.4.3 --- Asparagine synthetases --- p.107 / Chapter 3.5 --- Total glutamine synthetase enzyme activity --- p.117 / Chapter 4. --- Discussion --- p.126 / Chapter 4.1 --- Overexpressing PII and truncated PII in the transgenic plants --- p.126 / Chapter 4.2 --- The overall growth and development --- p.135 / Chapter 4.3 --- Chlorophyll --- p.135 / Chapter 4.4 --- Root length --- p.137 / Chapter 4.5 --- Expression of nitrogen assimilatory genes --- p.138 / Chapter 4.5.1 --- Genes encoding nitrate reductase --- p.138 / Chapter 4.5.2 --- Genes encoding glutamine synthetase --- p.140 / Chapter 4.5.3 --- Genes encoding asparagine synthetase --- p.141 / Chapter 4.6 --- Overall GS enzyme levels in the rosette leaves --- p.144 / Chapter 4.7 --- N/C ratio of the seed storage --- p.146 / Chapter 4.8 --- Proposed model for the roles of PII --- p.147 / Chapter 4.9 --- Conclusions --- p.149 / Chapter 4.10 --- Further studies --- p.150 / References --- p.152

Orientador: Enes Furlani Júnior / Banca: Liliane Santos de Camargos / Banca: Enio Tiago de Oliveira / Resumo: O pinhão-manso (Jatropha curcas L.) é uma planta conhecida e cultivada na América desde tempos remotos, porém, somente nas últimas três décadas passou a ser estudado agronomicamente. É considerada uma espécie promissora no processo de produção de biocombustíveis devido ao seu elevado teor de óleo nas sementes. Por tratar-se de uma planta ainda em fase de domesticação, os estudos acerca de seu crescimento e fisiologia ainda são escassos, porém necessários para a expansão da cultura em todo o país, por isso, o objetivo desta pesquisa foi analisar o crescimento e o metabolismo do nitrogênio de plantas jovens de J. curcas cultivadas sob quatro condições de sombreamento (0, 30, 50 e 70 % de cobertura) e quatro concentrações de nitrato (0, 15, 30 e 45 mM). Durante 120 dias as plantas foram tratadas e avaliadas biometricamente quanto à altura, diâmetro, número de folhas, área foliar e massas fresca e seca. Fisiologicamente analisou-se a atividade das enzimas redutase do nitrato e glutamina sintetase, proteína total solúvel, análise quantitativa de nitrato e amônia. Os resultados obtidos sugerem que com relação ao crescimento inicial J. curcas é responsiva ao sombreamento, como características ecofisiológicas que se refletem em adaptações morfológicas de expansão da área foliar, alongamento do pecíolo e maior crescimento em altura buscando ambientes com maior luminosidade, sendo que ambientes com sombreamento de 30% são eficazes no controle da temperatura foliar e retenção de água no substrato permitindo o melhor desenvolvimento das plantas, entretanto, níveis acima de 50% de sombreamento são prejudiciais ao crescimento inicial da espécie por provocarem intenso estiolamento e redução no número médio de folhas. A realização da adubação nitrogenada é de suma importância... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The jatropha (Jatropha curcas L.) is a plant known in America and cultivated since ancient times, but only in the last three decades began to be studied agronomy. It is considered a promising species for the biofuels production because its high oil content in seeds. It‟s a plant still under domestication because it, studies on their growth and physiology are still scarce, but necessary to the expansion of culture throughout the country, so the objective of this research was to analyze the growth and nitrogen metabolism in young plants of J. curcas grown under four conditions of shading (0, 30, 50 and 70% coverage) and four nitrate concentrations (0, 15, 30 and 45 mM). For 120 days the plants were treated and biometrically evaluated as to height, diameter, number of leaves, leaf surface area and fresh and dry mass. Physiologically, we analyzed the enzymes activity of the nitrate reductase and glutamine synthetase, total soluble protein, quantitative analysis of nitrate and ammonia. The results suggest that with respect to the initial growth J. curcas is responsive to the shading, with physiologic characteristics that reflected in morphological adaptations of leaf area expansion, petiole elongation and greater height growth looking environments with higher brightness, and shading environments with 30% are effective in leaf temperature control and water retention in the substrate allowing for better development of plants, however, levels above 50% shading is detrimental to early growth of the species to cause intense etiolation and reduction in the number of leaves. The nitrogen fertilizer is a paramount importance in the early development of plants, the start deficiency visual symptoms appear in the first month after germination. Nitrate concentrations exceeding 30 mM are harmful because they cause a reduction... (Complete abstract click electronic access below)

Includes bibliographical references (leaves [259]-290) Investigates nitrogen assimilation and metabolism in rumen bacteria with the object of understanding the basic process and their controls.