With a surge in future demand for hydrogen as a renewable fuel, the specific aim of this study was to develop a novel strategy in photosynthetic hydrogen production from green algae, which is one of the cleanest processes among existing hydrogen-production methodologies currently being explored. The novel strategy designed was a spectral-selective PSI-activation/PSII-deactivation protocol that would work to maintain a steady flow of electrons in the electron transport system in the light-dependent part of photosynthesis for delivery of electrons to hydrogenase for photo-hydrogen production. The strategy would work to activate PSI to assist in driving the electron flow, while partially deactivating PSII to a degree that it would still supply electrons, but would limit its photosynthetic oxygen production below the respiratory oxygen consumption so that an anoxic condition would be maintained as required by hydrogenase. This study successfully showed that the implementation of the spectral-selective PSIactivation/ PSII-deactivation strategy resulted in actual and relatively sustained photohydrogen production in Chlamydomonas reinhardtii cells, which had been dark-adapted for three hours immediately prior to exposure to a PSI-spectral selective radiation, which had a spectral peak at 692 nm, covering a narrow waveband of 681-701 nm, and was applied at 15 W m⁻². The optimal condition for the PSI-spectral-selective radiation (692 nm) corresponded with low cell density of 20 mg chlorophyll L⁻¹ ("chl" henceforth) with cells grown at 25⁰C. At this condition, the PSI-spectral-selective radiation induced the maximal initial hydrogen production rate of 0.055 mL H² mg⁻¹ chl h⁻¹ which statistically the same as that achieved under white light of 0.044 mL H² mg⁻¹ chl h⁻¹, a maximal total hydrogen production of 0.108 mL H² mg⁻¹ chl which significantly exceeded that under white light of 0.066 mL H² mg⁻¹ chl, and a maximal gross radiant energy conversion efficiency for hydrogen production of 0.515 μL H² mg⁻¹ chl L⁻¹ that statistically matched that under white light of 0.395 μL H² mg⁻¹ chl L⁻¹. The study also successfully demonstrated the reversibility feature of the novel strategy, allowing for the cells to alternately engage in photo-hydrogen production and to recover by simply switching on or off the PSI-spectral-selective radiation.

Ettlia oleoabundans, a freshwater green microalga, was grown under different environmental conditions to study its growth, lipid yield and quality for a better understanding of the fundamental physiology of this oleaginous species. E. oleoabundans showed steady increase in biomass under low temperature and low light intensity, and at high temperature lipid cell content significantly increased independent of nitrate depletion. Studies on light quality showed that red light treatment did not change the biomass concentration, but stimulated lipid yield especially oleic acid, the most desirable biodiesel precursor. Moreover, no photoreversibility in lipid production was observed when applying alternating short-term red and far-red lights, which left the phytochrome effect still an open question. In addition, carbon dioxide enrichment via an air sparging system significantly boosted exponential growth and increased carbon conversion efficiency. Finally, a practical study demonstrated the feasibility of growing E. oleoabundans for high lipid production using a diluted agricultural anaerobic waste effluent as the medium. Together, these studies showed the potential of E. oleoabundans as a promising high yield feedstock for the production of high quality biodiesel.

Orientador: Ciro Cesar Zanini Branco / Banca: Orlando Necchi Junior / Banca: Carla Ferragut / Resumo: Os efeitos provocados pela variação quantitativa e qualitativa da luz incidente sobre a estrutura das comunidades de macroalgas lóticas em riachos da região Centro-Sul do estado do Paraná foram investigados a partir de experimentos utilizando-se amostradores com substratos artificiais que modulam a quantidade e qualidade da luz incidente. Os resultados reveleram que as respostas das divisões algais isoladamente foram mais claras do que àquelas observadas para as comunidades de macroalgas como um todo. As algas verdes mostraram-se melhores adaptadas as condições com maiores energias luminosas. A espécie de cianobactéria registrou clara preferência por comprimentos de onda mais longos (faixa do vermelho). As algas vermelhas apesar de apresentarem baixos valores de abundância, aparentemente, preferiram condições levemente sombreadas e, como as cianobactérias, apresentaram maiores valores de abundância quando submetidas a luz vermelha. Neste contexto, o aparato fotossintético característico de cada divisão algal parece ser determinante para os seus comportamentos ecológicos, uma vez que desempenham funções adaptativas diante das diferentes condições de luminosidade / Abstract: The effects of light intensity and quality on the structure of lotic macroalgal communities in streams from the mid-southern region of Paraná State were investigated using artificial substrata that simulate different levels of light and specific wavelengths. The results showed that the abundance values of each algal divisions were clearer to that observed to global macroalgae communities. The green algae were better adaptated on higher light energies conditions. The cianobacteria species reported a clear preference to longer wavelengths (red light). Red algae, on the other hand, despite of the low abundance values, apparently prefer lightly shaded conditions and like blue-green algae, they showed better colonization on the red light. In this context, the characteristic photosynthetic apparatus of each division seems to be determinant to the ecological behavior of these communities once they play an important adaptative role face to the different light conditions / Mestre

Interspecific competition is comprised of both resource dependant and resource independent processes. While many studies have focused on the role that resource dependant competition plays in reducing crop yields, few have investigated whether resource independent effects, such as light or hormonal signaling, may contribute to these yield losses. The focus of this thesis was to investigate the role of the shade avoidance response in determining the onset and outcome of crop-weed competition in maize (Zea mays L.). The results of greenhouse and field trials demonstrate that shade avoidance in maize can be induced shortly after seedling emergence and that the effects of this early response can be detected throughout the entire life cycle of the crop. Seedlings exposed to a weedy or low red to far-red light (R/FR) environment at emergence displayed an initial increase in plant height and a reduction in the root-to-shoot ratio. These effects were followed by a reduction in the rate of leaf appearance (RLA) and a linear decline in biomass and leaf area (LA) as the duration of time spent in a weedy environment increased. Conversely, seedlings emerging in a weed-free or ambient R/FR environment were unaffected regardless the duration of time spent in the weedy environment. These effects of early crop-weed competition are distinct from those of plant population density (i.e., intraspecific competition). Results of a field trial demonstrated that intraspecific competition at a conventional density of 8 plants m-2 did not negatively impact RLA or biomass accumulation until well after the defined critical period for weed control. Moreover, intraspecific competition at 16 plants m-2 was not detected until the 12th leaf tip stage, suggesting that the effects of crop density are more closely associated with canopy closure than an early shade avoidance response. At maturity, seedlings that expressed shade avoidance at early stages of development set fewer kernels and partitioned less biomass to the developing ear. Shade avoidance also doubled the plant-to-plant variability in yield parameters without affecting the mean or frequency distribution of shoot biomass at maturity. When taken together, the results of these studies indicate that shade avoidance destabilizes stand productivity by increasing plant-to-plant variability in reproductive effort prior to intra- or interspecific competition for resources.

Made available in DSpace on 2014-06-11T19:23:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-03-02Bitstream added on 2014-06-13T20:49:52Z : No. of bitstreams: 1 tonetto_af_me_rcla.pdf: 1077078 bytes, checksum: f064a230b49104d5525789cc80a0787e (MD5) / Os efeitos provocados pela variação quantitativa e qualitativa da luz incidente sobre a estrutura das comunidades de macroalgas lóticas em riachos da região Centro-Sul do estado do Paraná foram investigados a partir de experimentos utilizando-se amostradores com substratos artificiais que modulam a quantidade e qualidade da luz incidente. Os resultados reveleram que as respostas das divisões algais isoladamente foram mais claras do que àquelas observadas para as comunidades de macroalgas como um todo. As algas verdes mostraram-se melhores adaptadas as condições com maiores energias luminosas. A espécie de cianobactéria registrou clara preferência por comprimentos de onda mais longos (faixa do vermelho). As algas vermelhas apesar de apresentarem baixos valores de abundância, aparentemente, preferiram condições levemente sombreadas e, como as cianobactérias, apresentaram maiores valores de abundância quando submetidas a luz vermelha. Neste contexto, o aparato fotossintético característico de cada divisão algal parece ser determinante para os seus comportamentos ecológicos, uma vez que desempenham funções adaptativas diante das diferentes condições de luminosidade / The effects of light intensity and quality on the structure of lotic macroalgal communities in streams from the mid-southern region of Paraná State were investigated using artificial substrata that simulate different levels of light and specific wavelengths. The results showed that the abundance values of each algal divisions were clearer to that observed to global macroalgae communities. The green algae were better adaptated on higher light energies conditions. The cianobacteria species reported a clear preference to longer wavelengths (red light). Red algae, on the other hand, despite of the low abundance values, apparently prefer lightly shaded conditions and like blue-green algae, they showed better colonization on the red light. In this context, the characteristic photosynthetic apparatus of each division seems to be determinant to the ecological behavior of these communities once they play an important adaptative role face to the different light conditions

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The quality of light can alter morphogenesis of plants through a series of processes mediated by light receptors, the use of nets with different spectral characteristics in the cultivation of certain vegetable crops has become very common in recent years. Against the great influence that the solar radiation on plants, accomplished this research with the objective of evaluating the effect of intensity and spectral quality of light transmitted through the netting photoselectives in the growth and development of curly lettuce plants, as well as in microclimatic elements in a protected environment. The experiment featured four microhabitats: control - without net, net-term Aluminet reflector; Chromatinet netting blue and red, all with 35% shading, fixed at 0.90 m above the bed cultivation. The study was conducted in two stages, the first assessing the effect of net in the development of lettuce seedlings cultivar 'Solaris' floating produced hydroponically in winter season, rated the characteristics: number of leaves, leaf area, and fresh biomass dried roots, stems and leaves, stem length, why shoot / root and specific leaf area, and the second step verifying the influence of nets in growth and development, as well as the anatomy and physiology of lettuce cultivars 'Vera' 'Vanda' and 'Solaris' hydroponically-type solution of laminar flow bench during final production. The growth evaluations were done every seven days in two cropping seasons, autumn and winter, and the parameters were evaluated: number of leaves, leaf area, stem length, fresh weight and dry leaf and root dry weight. At the end of the production cycle were evaluated the anatomical and physiological parameters, which were stomatal density and morphology as well as the pigment content in lettuce leaves. With these results it is evident that the different nets modify microclimatic elements, presenting differences spectral transmittance, absorbance and reflectance. In the seedling stage thermo-reflective and red mesh showed a higher accumulation of biomass in lettuce compared to the environment without net and blue net. At the stage of final production bench observed that the cultivation environment promotes anatomical and physiological changes in lettuce and the environment without shading net showed higher dry biomass. In both steps the experimental blue net showed lower development of lettuce compared to other environments. / A qualidade de luz pode alterar a morfogênese das plantas por meio de uma série de processos mediados por receptores de luz. A utilização de malhas com diferentes características espectrais no cultivo de algumas espécies olerícolas tornou-se muito comum nos últimos anos. Diante da grande influência que a radiação solar exerce sobre os vegetais, realizou-se esta pesquisa com o objetivo de avaliar o efeito da intensidade e da qualidade espectral da luz transmitida pelas malhas fotoseletivas no crescimento e desenvolvimento de plantas de alface crespa, assim como nos elementos microclimáticos em ambiente protegido. O experimento contou com quatro microambientes: testemunha sem malha; malha Aluminet termo-refletor; malha Chromatinet azul e malha Chromatinet vermelha, todas com 35% de sombreamento, fixadas a 0,90 m acima dos leitos de cultivo. O estudo foi conduzido em duas etapas distintas, a primeira avaliando o efeito das malhas no desenvolvimento de mudas de alface cultivar Solaris‟ produzidas em sistema hidropônico floating na estação do inverno, avaliado as características: número de folhas, área foliar, fitomassa fresca e seca de raízes, caules e folhas, comprimento do caule, razão parte aérea/raiz e área foliar específica, e a segunda etapa verificando a influência das malhas no crescimento e desenvolvimento, assim como na anatomia e fisiologia de plantas de alface cultivares Vera‟, Vanda‟ e Solaris‟ em sistema hidropônico do tipo fluxo laminar de solução na fase de bancada de produção final. As avaliações de crescimento foram feitas a cada sete dias em duas épocas de cultivo, outono e inverno, e os parâmetros avaliados foram: número de folhas, área foliar, comprimento do caule, fitomassa fresca e seca de folha e fitomassa seca de raiz. Ao final do ciclo de produção avaliou-se os parâmetros anatômicos e fisiológicos, que foram: morfometria e densidade estomática assim como o teor de pigmentos nas folhas de alface. Com os resultados obtidos fica evidente que as diferentes malhas modificam os elementos microclimáticos, apresentando diferenças espectrais de transmitância, absorbância e refletância. Na fase de muda as malhas termo-refletor e malha vermelha apresentaram maior acúmulo de fitomassa em plantas de alface comparado ao ambiente sem malha e malha azul. Na fase de bancada de produção final observou-se que o ambiente de cultivo promove alterações anatômicas e fisiológicas em plantas de alface e o ambiente sem malha de sombreamento apresentou maior acúmulo de fitomassa. Em ambos as etapas experimentais a malha azul apresentou menor desenvolvimento das plantas de alface comparado aos demais ambientes.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2018-06-11T16:27:45Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) resumo_dissertacao_daniele_de_souza_masiero.pdf: 23649 bytes, checksum: 3c666bef05b41b7c3704d03fde630a6b (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-06-11T16:56:41Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) resumo_dissertacao_daniele_de_souza_masiero.pdf: 23649 bytes, checksum: 3c666bef05b41b7c3704d03fde630a6b (MD5) / Made available in DSpace on 2018-06-11T16:56:42Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) resumo_dissertacao_daniele_de_souza_masiero.pdf: 23649 bytes, checksum: 3c666bef05b41b7c3704d03fde630a6b (MD5) Previous issue date: 2017-06-27 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / O cultivo in vitro é uma importante ferramenta para a propagação da batata-doce e diferentes fatores podem interferir na exequibilidade desta técnica, como a composição do meio de cultura e o microambiente no qual as plantas são expostas. O presente estudo teve como objetivo avaliar o desempenho das cultivares BRS Amélia, BRS Cuia e BRS Rubissol de batata-doce, cultivadas in vitro em duas concentrações de sacarose, duas combinações de espectro luminoso e dois sistemas de cultivo. Para isso o trabalho foi dividido em três experimentos: no primeiro, testou-se duas concentrações de sacarose em biorreator de imersão temporária configurado na combinação de espectro vermelho e branco; no segundo utilizou-se duas concentrações de sacarose em biorreator de imersão temporária configurado na combinação de espectro vermelho e azul; no terceiro, testou-se duas concentrações de sacarose em meio semissólido configurado na combinação de espectro vermelho e branco. O delineamento experimental utilizado foi inteiramente casualizado, em esquema fatorial 2x3: duas concentrações de sacarose (15g L-1 ou 30g L-1) e 3 cultivares (BRS Amélia, BRS Cuia e BRS Rubissol). As variáveis analisadas foram: comprimento de parte aérea, número médio de folhas, número e comprimento de raízes, número e comprimento de brotações, índices de clorofila a, b e total e porcentagem de aclimatização. Para os três experimentos o uso de 30g L-1 de sacarose no meio de cultivo resultou nas maiores médias em todas as variáveis analisadas e a cultivar BRS Cuia foi a que apresentou o melhor desempenho nas condições estudadas. No sistema semissólido foi possível verificar um grande número e comprimento de raízes, enquanto que no sistema de imersão temporária foi verificada presença de brotações em todas as cultivares e maiores médias de comprimento de parte aérea. Concluiu-se que a concentração de 30g L-1 de sacarose no meio de cultura proporciona taxas satisfatórias de crescimento e aclimatização das três cultivares em estudo, sendo recomendada para a micropropagação da espécie. A combinação de espectro luminoso vermelho e azul proporciona maior comprimento de parte aérea, número de folhas e comprimento de raiz quando comparado ao espectro vermelho e branco. A „BRS Rubissol‟ tem melhor desempenho no sistema convencional, a „BRS Amélia‟ no sistema de imersão temporária, enquanto a „BRS Cuia‟ desenvolve-se igualmente independente do sistema de cultivo utilizado. / In vitro cultivation is an important tool for the propagation of sweet potatoes and different factors may interfere with the feasibility of this technique, such as the composition of the culture medium and the microenvironment in which the plants are exposed. The objective of this study was to evaluate the performance of BRS Amélia, BRS Cuia and BRS Rubissol sweet potato cultivars grown in vitro in two concentrations of sucrose, two combinations of light spectrum and two cultivation systems. For the work in division in three experiments: in the first, two concentrations of sucrose in temporary immersion bioreactor configured in the combination of red and white spectrum were tested; In the second, two concentrations of sucrose in a temporary immersion bioreactor configured in the combination of red and blue spectrum are used; In the third, two concentrations of sucrose in semisolid medium configured in the red and white spectrum combination were tested. The experimental design was completely randomized in a factorial 2x3: two concentrations of sucrose (15g L-1 or 30g L-1) and 3 cultivars (BRS Amélia, BRS Cuia and BRS Rubissol). The analyzed variables were: shoot length, number of leaves, number and length of roots, number and length of buds, chlorophyll a, b and total rate and percentage of acclimatization. For the three experiments, the use of 30g L-1 of sucrose in the culture medium resulted in the highest averages in all analyzed variables and the cultivar BRS Cuia was the one that presented the best performance under the conditions studied. In the semisolid system it was possible to verify a large number and length of roots, whereas in the temporary immersion system, the presence of sprouts was verified in all the cultivars and larger averages of shoot length. It was concluded that the concentration of 30 g L-1 of sucrose in the culture medium provides satisfactory rates of growth and acclimatization of the three cultivars under study, being recommended for the micropropagation of the species. The combination of red and blue light spectrum provides greater shoot length, number of leaves and root length when compared to the red and white spectrum. 'BRS Rubissol' performs better in the conventional system, 'BRS Amelia' in the temporary immersion system, while 'BRS Cuia' is also developed independent of the culture system used.

Made available in DSpace on 2014-08-20T14:22:08Z (GMT). No. of bitstreams: 1 Dissertacao_Georgea_Soares_Figueiredo.pdf: 728913 bytes, checksum: b001e52b25d78faa26942f0b6de87631 (MD5) Previous issue date: 2009-03-06 / The Japanese quince (Chaenomeles sinensis Koehne) can be used as rootstocks for quince, pear, loquat trees and as cultivar canopy. The use of quince by seeds, as rootstocks for other quince species and cultivars, has been shown viable. However, the inconvenient in the sexual reproduction is obtaining of not uniform seedlings, since it is not desired in the commercial plantations establishment due gene segregation. The seedlings production technology for Japanese quince by vegetative propagation is not defined, due low percentage of rooting. Thus, the tissue culture presents as a viable alternative in the clonal orchards development or seedlings commercial production. Experiments were performed to determine a protocol of in vitro establishment this specie, where was tested the disinfectant with chlorine appropriate for vegetal material, as well as cytokinin, flask cover, salt concentration of culture medium, culture medium, BAP cytokinin concentration and light quality. It could be conclude that calcium hypochlorite disinfectant is effective in the explants disinfestations, and the BAP provides better results in the establishment than 2iP and Zea cytokinins. Sealed flasks with cotton instead aluminum, reduce the explant oxidation and the original salt concentration of MS medium promotes better explant establishment. The WPM medium showed higher results than MS medium and BAP at 1mg.L-1 or 2mg.L-1 concentration promotes an increase in the number and length of sprouting, as well as the use of red light instead white and green light. / O marmeleiro japonês Chaenomeles sinensis Koehne pode ser utilizado como porta-enxerto para marmeleiros, pereiras, nespereiras e também como cultivar copa. O uso deste marmeleiro via seminífera, como porta-enxerto para outras espécies e cultivares de marmelo, tem se mostrado viável, o inconveniente na reprodução sexual é a obtenção de plântulas desuniformes, o que não é desejado no estabelecimento de plantios comerciais, devido à segregação gênica. A tecnologia de produção de mudas para o marmeleiro Japonês por propagação vegetativa não está ainda definida, devido a baixa porcentagem de enraizamento, sendo assim a cultura de tecidos apresenta-se como uma alternativa viável na formação de pomares clonais ou produção comercial de mudas. Foram realizados experimentos a fim de determinar um protocolo de estabelecimento in vitro desta espécie, onde foi testado o desinfestante a base de cloro adequado a desinfestação do material vegetal, bem como o a citocinina, tipo de vedação dos frascos, concentração salina do meio de cultura, meio de cultura, concentração da citocinina BAP e qualidade de luz. A partir dos resultados obtidos pode-se concluir que o desinfestante hipoclorito de cálcio é eficiente na desinfestação dos explantes, e a citocinina BAP promove melhores resultados no estabelecimento, comparada as citocininas 2iP e Zea. Frascos vedados com algodão, ao invés de alumínio, reduzem a oxidação dos explantes e o meio MS na sua concentração salina original promoveu melhor estabelecimento dos explantes. O meio WPM demonstrou resultados superiores ao meio MS e a citocinina BAP na concentração de 1mg.L-1 ou 2mg.L-1 promove aumento no número e comprimento das brotações, assim como a utilização de luz vermelha quando comparada a luz branca e a luz verde.

C4 plants have a biochemical carbon concentrating mechanism (CCM) that increases CO2 concentration around Rubisco in the bundle sheath (BS). Maize CCM has two CO2 delivery pathways to the Bundle Sheath (BS) (respectively via malate, MAL or aspartate, ASP); rates of PGA reduction, carbohydrate synthesis and PEP regeneration vary between BS and Mesophyll (M) cells. For these anatomical and biochemical complexities, C4 plants are highly sensitive to light conditions. Under limiting light, the activity of the CCM generally decreases, causing an increase in leakiness, (Φ), the ratio of CO2 retrodiffusing from the BS relative to C4 carboxylation processes. This increase in Φ had been theoretically associated with a decrease in biochemical operating efficiency (expressed as ATP cost of gross assimilation, ATP / GA) under low light and, because a proportion of canopy photosynthesis is carried out by shaded leaves, to potential productivity losses at field scale. In C4 leaves, because of the concentric anatomy, light reaches M cells before the deeper BS (Evans et al., 2007), and could alter the energetic partitioning balance between BS and M and potentially cause efficiency losses. In this experimental programme I investigated strategies deployed by C4 plants to adjust operating efficiency under different illumination conditions. Firstly, maize plants were grown under high and low light regimes (respectively HL, 600 vs LL, 100 μE m-2 s-1). Short term acclimation of Φ was compared from isotopic discrimination (Δ), gas exchange and photochemistry using an improved modelling approach which does not suffer from elements of circularity. Long term acclimation to low light intensities brought about physiological changes which could potentially increase the operating efficiency under limiting ATP supplies. Secondly, profiles of light penetration across a leaf were used to derive the potential ATP supply for M and BS cells induced by changing light quality. Empirical measurements of net CO2 uptake, ATP production rate and carbon isotope discrimination were made on plants under a low light intensity. The overall conversion efficiency was not affected by light quality. A comprehensive metabolic model highlighted the importance of both CO2 delivery pathways in maize. Further, metabolic plasticity allowed the balancing of ATP and NADPH requirements between BS and M. Finally, I tested the hypothesis that plants can modify their physiology so as to reach a status of higher operating efficiency when exposed to high light and then to low light, so as to mimic the transition which leaves undergo when shaded by newly emerging leaves in a crop canopy. Plants were grown under high light and low light for three weeks, then, HL plants were transferred to low light for a further three weeks. Re-acclimation was very effective in reducing ATP cost of net assimilation under low light intensities. In addition, the hyperbolic leakiness increase observed under low light intensities was not associated to operating efficiency loss. Overall, in the three experimental Chapters I showed compelling theoretical and empirical evidence proving the hypothesis that C4 plants deal with low light conditions and with different light qualities without losing operating efficiency.

No description available.