The aim of this study is to test the limits of photocatalytic reduction of CO2 over Pt and light harvesting dye promoted TiO2 films under UV and visible light. Thick and thin TiO2 film catalysts are coated onto 1 cm long glass beads via a common sol-gel procedure and dip coating technique. TiO2 thin films were promoted by Pt and three different light harvesting molecules: RuBpy (Tris (2,2&rsquo / &ndash / bipyridyl) ruthenium (II) chloride hexahydrate) , BrGly (1,7-dibromo-N,N&rsquo / -(t-butoxycarbonyl-methyl)-3,4:9,10-perylene-diimide) and BrAsp (1,7-dibromo-N,N&rsquo / -(S-(1-t-butoxy-carbonyl-2-t-butoxycarbonyl-methyl)-ethyl)- 3,4:9,10-perylenediimide). Their SEM, XRD, UV-Vis spectroscopy and hydrogen chemisorption characterizations are performed. Reaction tests are performed for the catalysts under UV and visible light. The only quantifiable reaction product was methane. With RuBpy containing catalysts hydrogen production was observed under UV light, but not quantified. The results indicated that Pt addition resulted in higher yields in UV experiments. The presence of light harvesting molecules resulted in increase in photocatalytic activity for thin films, whereas it resulted in no change or decrease for the thick films. The latter case may occur due to the UV filtering effect of these dyes. Use of dyes (with visible range absorption bands) as promoters made visible light excitation possible. This resulted in photocatalytic activity under visible light, which was not observed with unpromoted and Pt promoted TiO2 thin film catalysts. Under visible light methane was the only quantified photoreduction product. CO evolution was also observed, but not quantified. The photocatalytic activities of the dye promoted TiO2 were in the order of RuBpy~BrAsp&gt / BrGly. The methane yields of visible light experiments were one order of magnitude lower than the ones under UV light.

The purpose of this study was to identify the relative predictive influences of prior knowledge, meaningful learning orientation, formal reasoning ability and mode of instruction on understanding in photosynthesis and respiration in plants concepts. Two hundred thirty three 8th grade students from six classes of one elementary school in Ankara participated in this study. The study was carried out during the 2004-2005 Fall semester. Students in the experimental group (N=117) received conceptual change instruction, and the students in the control group (N=116) received traditional instruction. Two-tier multiple choice diagnostic test, &ldquo / Photosynthesis and Respiration in Plants Concept Test&rdquo / developed by Haslam and Treagust (1987), was used to determine students&rsquo / understanding of photosynthesis and respiration in plants concepts. The test was administered to the sample prior to the treatment as pre-test, and after the treatment as post-test. The pre-test scores were used as prior knowledge of students. Students&rsquo / reasoning abilities were measured by the &ldquo / Test of Logical Thinking&rdquo / and their learning orientations were measured by &ldquo / Learning Approach Questionnaire&rdquo / . The results of the study indicated that students held several misconceptions concerning photosynthesis and respiration in plants concepts. Significant differences between the experimental group and control group with respect to understanding of the concept were found in favor of experimental group. The main predictor of achievement in the experimental group was students&rsquo / prior knowledge, while it was reasoning ability in the control group. Meaningful learning orientation accounted for a small amount of variance in the experimental group but it did not contribute to understanding on post-test scores in traditional group.

ABSTRACT Assessing the impact of herbivory on plant growth and reproduction is important to predict the success of biocontrol of invasive plants. Leaf area production is most important, as photosynthesis provides the foundation for all plant growth and fitness. High levels of defoliation generally reduce the productivity of plants. However, leaf area production fluctuates during the season and compensational growth may occur, which both complicate accurate estimations of defoliation impacts. Under field conditions the interaction with neighbouring species and the availability of soil nutrients need to be assessed in order to gauge long term effects of weed invasions on natural environments. In this thesis I have investigated seasonal leaf area dynamics in Buddleia davidii following repeated artificial defoliation, to quantify compensational leaf production and to understand the regulatory mechanisms involved. The impact of defoliation on photosynthesis, seed production, germination and nitrogen translocation patterns were analysed. Finally, possible facilitation between B. davidii and a native nitrogen fixer, Coriaria arborea, and the impact of B. davidii on soil nutrient availability were investigated. In defoliated B. davidii, increased node production (34%), leaf size (35%) and leaf longevity (12%) resulted in 52% greater total emergent leaf area in the short term. However, with time and diminishing tissue resources the compensation declined. No upregulation of photosynthesis was observed in pre-existing leaves. Compensational leaf area production occurred at the expense of reproduction but the germination capacity of individual seeds was unaffected. In B. davidii, nitrogen reserves are stored in old leaves. Thus, the defoliation-induced decline in tissue reserves led to changes in the remobilisation pattern and increased the importance of soil uptake but biomass production especially that of roots had declined significantly (39%). Slight facilitation effects from the neighbouring nitrogen fixer and VA-mycorrhizae were observed on B. davidii in the field, while its impact on soil chemistry during spring was negligible. Defoliation of B. davidii resulted in priority allocation of resources to compensational leaf growth and a concomitant reduction in flower and seed production. The compensational leaf production greatly increased the demand for nitrogen, while continued leaf removal decreased the pool of stored nitrogen. This led to changes in nitrogen remobilisation and an increased importance of root uptake. However, the significant decline in root growth will likely impair adequate nutrient uptake from the soil, which is especially important where B. davidii invades nutrient poor habitats and will increase the success of biocontrol of the species. While mycorrhizae increase nutrient accessibility for B. davidii, it is likely that the additional stress of defoliation will negate the small facilitative effects from nitrogen-fixing species like C. arborea. This research provides new insights into the mechanisms regulating leaf area dynamics at the shoot level and systemic physiological responses to defoliation in plants, such as nitrogen translocation. The compensation in leaf area production was considerable but only transitory and thus, the opportunity to alleviate effects of leaf loss though adjustment of light capture limited. However, to ascertain that photosynthesis at whole plant level does not increase after defoliation, more detailed measurements especially on new grown leaves are necessary. In general, defoliation had greatly reduced plant growth and performance so that an optimistic outlook for controlling this species can be given. Conclusions about the wider impacts of B. davidii on soil chemistry and community function will require further research.

[Truncated abstract] In the most common (hydrological) viewpoint, vegetation is a

Thesis (M.S.); Submitted to Iowa State Univ., Ames, IA (US); 19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2488" Tugba Kalem. US Department of Energy 12/19/2004. Report is also available in paper and microfiche from NTIS.

Thesis (M.S.)--Wake Forest University. Dept. of Biology, 2003. / Vita. Includes bibliographical references (leaves 51-57).

CNPq; Fundação Araucária / A região do Sudoeste do Paraná apresenta o setor agrário bem desenvolvido, com ênfase na produção leiteira de pela agricultura familiar. A base nutricional dessas propriedades são as pastagens formadas por gramíneas tropicais, as quais apresentam uma diminuição em sua produção de fitomassa em determinada época do ano, com a queda na intensidade luminosa e temperatura. A implantação de pastagens temperadas, principalmente de aveia, é uma estratégia comum na região para a atividade. Avaliou-se os efeitos dos níveis de nitrogênio no crescimento, desenvolvimento, acúmulo de fitomassa, composição química, cinética ruminal e produção de gases de efeito estufa. O trabalho foi conduzido na UTFPR-DV nos anos de 2013 e 2014, em blocos ao acaso com quatro níveis de adubação N (0,60, 120 e 240 KgN.ha-1) com 3 repetições, em períodos de corte a cada 21 dias, usando-se cultivares de aveia branca (Avena sativa L.) URS Guapa e IPR126. Foram analisados taxa de assimilação de CO2, concentração intracelular de CO2, taxa de transpiração, temperatura da folha, teor de clorofila, produção de fitomassa, proteína, FDN, lignina, EE, produção de gás em relação aos teores de carboidratos de rápida degradação e de degradação lenta, bem como CH4, CO2 e N2O.Para IPR 126 no ano de 2013 houve efeito significativo nas variáveis PB, CT, k1, eficiência do uso da água, transpiração e temperatura foliar, enquanto que para o ano de 2014, as variáveis foram CT, vf1, k1, vf2, número de perfilhos e eficiência do uso da água. Para a cultivar URS Guapa, no ano de 2013, houve efeito significativo para as variáveis peso das folhas (em gramas) e temperatura foliar, enquanto que no ano de 2014, número de perfilhos, transpiração e temperatura foliar foram significativos.Observou-se que a cultivar IPR 126 foi mais influenciada pelos níveis de adubação que a cultivar URS Guapa, em todos os anos e os gases de efeito estufa não foram afetados. / The Southwest region of Paraná presents the well-developed agrarian sector, with emphasis on dairy production from family farming. The nutritional base of these properties are pastures formed by tropical grasses, which present a decrease in their phytomass production at a given time of year, with the decrease in luminous intensity and temperature. The implementation of temperate pastures, mainly of oats, is a common strategy in the region for the activity. The effects of nitrogen levels on growth, development, phytomass accumulation, chemical composition, ruminal kinetics and greenhouse gas production were evaluated. The work was conducted in UTFPR-DV in the years of 2013 and 2014, in randomized blocks with four levels of N fertilization (0.60, 120 and 240 KgN.ha-1) with 3 replications, in cut-off times every 21 Days, using white oats (Avena sativa L.) URS Guapa and IPR126. Were analysed CO2 assimilation rates, intracellular CO 2 concentration, transpiration rate, leaf temperature, chlorophyll content, phytomass production, protein, NDF, lignin, EE, gas production in relation to fast-degraded carbohydrate. In the year of 2013, there was a significant effect on the variables PB, CT, k1, water use efficiency, transpiration and foliar temperature, while for the year 2014, Variables were CT, vf1, k1, vf2, number of tillers and water use efficiency. For the cultivar URS Guapa, in the year 2013, there was a significant effect for the variables leaf weight (in grams) and leaf tempreture, while in the year 2014, number of tillers, transpiration and leaf temperartura were significant. It was observed that The cultivar IPR 126 was more influenced by levels of fertilization than the cultivar URS Guapa, in all years and greenhouse gases were not affected.

Biochemical and biophysical methods in combination with electron microscopy were used to investigate structure and function of pigment-protein complexes in thylakoid membranes of various photosynthetic organisms.

Made available in DSpace on 2016-08-12T19:15:20Z (GMT). No. of bitstreams: 1 ValmorET_DISSERT.pdf: 1152615 bytes, checksum: db476e005af6cccba35d383e70cb2af7 (MD5) Previous issue date: 2012-03-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Tabebuia impetiginosa is a tree species, known as pau d'arco or ipe-roxo. It is found in Caatinga areas, and is of great importance to this biome, its wood is much appreciated, and because it contains in its bark substances that act against cancer. This species has been used in land restoration programs. Species of this biome, such as ipe-roxo, present several morphophysiological changes as a way to adapt to the dry seasons of the year. The study of these changes is of great importance, and it s necessary to understand these mechanisms so that we can manage and conserve these species. Therefore, this study aims to evaluate the ecophysiological behavior of Tabebuia impetiginosa in response to water stress and rehydration. For this purpose an experiment was conducted in a greenhouse at the Universidade Federal Rural do Semi-Arido. The fruits were collected from trees of the same University and sowed in soil from two locations, Mossoro, and Angicos, this one collected in an area in process of desertification. When the seedlings reached nine months in the dry season, the treatments were applied, consisted of a set of two factors. the first one were the two soil types (Mossoró and Angicos) and the second, two water regimes with three replications, with each repetition represented by three plants. The evaluations were performed every three days during the period of suspension of irrigation in seedlings with and without irrigation, and the return of irrigation determined by monitoring the onset of leaf fall in plants subjected to irrigation suspension. After this period the plants were rehydrated, and evaluations done until the photosynthesis rates of the seedlings that were subjected to irrigation suspension equalized to the ones that were not submitted. The variables investigated were photosynthesis (A), stomatal conductance (E), internal CO2 concentration (Ci), transpiration (E), water use efficiency (A/E), carboxylation efficiency (A/Ci) and leaf water potential (Ψw) at predawn and midday.The soil of Mossoro presented greater rates of A and E in some evaluations when exposed to good water conditions when compared to the Angicos soil. This response in this condition was not related to gs. When subjected to stress, the of ipe-roxo seedlings in Angicos soil reduced their leaf Ψw before the seedlings grown in Mossoro soil. When rehydrated, seedlings grown in Angicos soil recovered their leaf Ψw before the plants grown in Mossoro soil. Regardless of the soil, water stress affected A, E, gs, and Ci, with decrease of these variables and rapid recovery after rehydration. In contrast, there was an increase in A/E during water stress, and this occurred earlier in plants grown in Mossoro soil. With water stress there was a the reduction of leaf Ψw, this reduction being found earlier in Angicos soil and in predawn. The Tabebuia impetiginosa presents itself as an investor plant, with an ability to reduce its leaf Ψw in water shortage conditions / Tabebuia impetiginosa é uma espécie arbórea, conhecida como pau-d`arco ou ipê-roxo. Encontrada em áreas da Caatinga, é de grande importância para esse bioma, possuindo madeira muito apreciada, e por conter em sua casca substâncias que agem contra o câncer. Essa espécie vem sendo usada em programas de recuperação de áreas degradadas. Espécies desse bioma, como o Ipê-roxo, apresentam diversas alterações morfofisiológicas como forma de adaptação às épocas secas do ano. O estudo dessas alterações é de grande importância, sendo necessário conhecer esses mecanismos para que se possa manejar e conservar essas espécies. Logo, objetiva-se nesse estudo avaliar o comportamento ecofisiológico de Tabebuia impetiginosa em resposta ao estresse hídrico e a reidratação. Para isso foi realizado um experimento na casa de vegetação da Universidade Federal Rural do Semi-Árido. Os frutos foram coletados em árvores da mesma Universidade e a semeadura realizada em solos de duas localidades, Mossoró, e Angicos, esse último coletado em uma área em processo de desertificação. Quando as mudas atingiram nove meses, na estação seca do ano, foram aplicados os tratamentos, constituídos de um conjunto de dois fatores, sendo o primeiro, dois tipos de solo (Mossoró e Angicos) e o segundo, dois regimes hídricos com três repetições, com cada repetição representada por três plantas. O delineamento experimental foi em blocos casualizados. As avaliações foram realizadas a cada três dias, durante o período de suspensão da irrigação, em mudas com e sem irrigação, sendo a retomada da irrigação determinada pelo monitoramento do início da queda das folhas, nas plantas submetidas à suspensão. Após esse período as mudas foram reidratadas, e as avaliações realizadas até que as taxas de fotossíntese das mudas que foram submetidas à suspensão igualassem às que não foram submetidas. As variáveis avaliadas foram fotossíntese (A), condutância estomática (gs), concentração interna de CO2 (Ci), transpiração, Eficiência de uso da água (A/E), Eficiência de carboxilação (A/Ci) e o potencial hídrico foliar (Ψw) ao pré-amanhecer e ao meio-dia. O solo de Mossoró apresentou maiores taxas de A e E em determinados períodos de avaliação quando submetido a boa condição hídrica em relação ao solo de Angicos. Essa resposta, nessa condição, não esteve relacionada à gs. Quando submetido ao estresse, as mudas de Ipê-roxo no solo de Angicos reduziram seu Ψw foliar antes das mudas cultivada no solo de Mossoró. E quando reidratadas, mudas cultivadas no solo de Angicos recuperaram seu Ψw foliar antes do solo de Mossoró. Independente do solo estudado o estresse hídrico afeta A, E, gs, Ci, com decréscimo dessas variáveis e rápidas recuperações após a reidratação. Diferentemente, a A/E, presenta um aumento com o estresse hídrico, sendo esse verificado antes em mudas cultivadas no solo de Mossoró. Com o estresse hídrico ocorre a redução do Ψw foliar, sendo essa redução encontrada antes no solo de Angicos e no período anterior ao amanhecer. A Tabebuia impetiginosa apresenta-se como uma espécie investidora, apresentando capacidade de reduzir seu Ψw foliar em condições de falta de água

Made available in DSpace on 2016-08-12T19:18:41Z (GMT). No. of bitstreams: 1 ValmorET_DISSERT.pdf: 1152615 bytes, checksum: db476e005af6cccba35d383e70cb2af7 (MD5) Previous issue date: 2012-03-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Tabebuia impetiginosa is a tree species, known as pau d'arco or ipe-roxo. It is found in Caatinga areas, and is of great importance to this biome, its wood is much appreciated, and because it contains in its bark substances that act against cancer. This species has been used in land restoration programs. Species of this biome, such as ipe-roxo, present several morphophysiological changes as a way to adapt to the dry seasons of the year. The study of these changes is of great importance, and it s necessary to understand these mechanisms so that we can manage and conserve these species. Therefore, this study aims to evaluate the ecophysiological behavior of Tabebuia impetiginosa in response to water stress and rehydration. For this purpose an experiment was conducted in a greenhouse at the Universidade Federal Rural do Semi-Arido. The fruits were collected from trees of the same University and sowed in soil from two locations, Mossoro, and Angicos, this one collected in an area in process of desertification. When the seedlings reached nine months in the dry season, the treatments were applied, consisted of a set of two factors. the first one were the two soil types (Mossoró and Angicos) and the second, two water regimes with three replications, with each repetition represented by three plants. The evaluations were performed every three days during the period of suspension of irrigation in seedlings with and without irrigation, and the return of irrigation determined by monitoring the onset of leaf fall in plants subjected to irrigation suspension. After this period the plants were rehydrated, and evaluations done until the photosynthesis rates of the seedlings that were subjected to irrigation suspension equalized to the ones that were not submitted. The variables investigated were photosynthesis (A), stomatal conductance (E), internal CO2 concentration (Ci), transpiration (E), water use efficiency (A/E), carboxylation efficiency (A/Ci) and leaf water potential (Ψw) at predawn and midday.The soil of Mossoro presented greater rates of A and E in some evaluations when exposed to good water conditions when compared to the Angicos soil. This response in this condition was not related to gs. When subjected to stress, the of ipe-roxo seedlings in Angicos soil reduced their leaf Ψw before the seedlings grown in Mossoro soil. When rehydrated, seedlings grown in Angicos soil recovered their leaf Ψw before the plants grown in Mossoro soil. Regardless of the soil, water stress affected A, E, gs, and Ci, with decrease of these variables and rapid recovery after rehydration. In contrast, there was an increase in A/E during water stress, and this occurred earlier in plants grown in Mossoro soil. With water stress there was a the reduction of leaf Ψw, this reduction being found earlier in Angicos soil and in predawn. The Tabebuia impetiginosa presents itself as an investor plant, with an ability to reduce its leaf Ψw in water shortage conditions / Tabebuia impetiginosa é uma espécie arbórea, conhecida como pau-d`arco ou ipê-roxo. Encontrada em áreas da Caatinga, é de grande importância para esse bioma, possuindo madeira muito apreciada, e por conter em sua casca substâncias que agem contra o câncer. Essa espécie vem sendo usada em programas de recuperação de áreas degradadas. Espécies desse bioma, como o Ipê-roxo, apresentam diversas alterações morfofisiológicas como forma de adaptação às épocas secas do ano. O estudo dessas alterações é de grande importância, sendo necessário conhecer esses mecanismos para que se possa manejar e conservar essas espécies. Logo, objetiva-se nesse estudo avaliar o comportamento ecofisiológico de Tabebuia impetiginosa em resposta ao estresse hídrico e a reidratação. Para isso foi realizado um experimento na casa de vegetação da Universidade Federal Rural do Semi-Árido. Os frutos foram coletados em árvores da mesma Universidade e a semeadura realizada em solos de duas localidades, Mossoró, e Angicos, esse último coletado em uma área em processo de desertificação. Quando as mudas atingiram nove meses, na estação seca do ano, foram aplicados os tratamentos, constituídos de um conjunto de dois fatores, sendo o primeiro, dois tipos de solo (Mossoró e Angicos) e o segundo, dois regimes hídricos com três repetições, com cada repetição representada por três plantas. O delineamento experimental foi em blocos casualizados. As avaliações foram realizadas a cada três dias, durante o período de suspensão da irrigação, em mudas com e sem irrigação, sendo a retomada da irrigação determinada pelo monitoramento do início da queda das folhas, nas plantas submetidas à suspensão. Após esse período as mudas foram reidratadas, e as avaliações realizadas até que as taxas de fotossíntese das mudas que foram submetidas à suspensão igualassem às que não foram submetidas. As variáveis avaliadas foram fotossíntese (A), condutância estomática (gs), concentração interna de CO2 (Ci), transpiração, Eficiência de uso da água (A/E), Eficiência de carboxilação (A/Ci) e o potencial hídrico foliar (Ψw) ao pré-amanhecer e ao meio-dia. O solo de Mossoró apresentou maiores taxas de A e E em determinados períodos de avaliação quando submetido a boa condição hídrica em relação ao solo de Angicos. Essa resposta, nessa condição, não esteve relacionada à gs. Quando submetido ao estresse, as mudas de Ipê-roxo no solo de Angicos reduziram seu Ψw foliar antes das mudas cultivada no solo de Mossoró. E quando reidratadas, mudas cultivadas no solo de Angicos recuperaram seu Ψw foliar antes do solo de Mossoró. Independente do solo estudado o estresse hídrico afeta A, E, gs, Ci, com decréscimo dessas variáveis e rápidas recuperações após a reidratação. Diferentemente, a A/E, presenta um aumento com o estresse hídrico, sendo esse verificado antes em mudas cultivadas no solo de Mossoró. Com o estresse hídrico ocorre a redução do Ψw foliar, sendo essa redução encontrada antes no solo de Angicos e no período anterior ao amanhecer. A Tabebuia impetiginosa apresenta-se como uma espécie investidora, apresentando capacidade de reduzir seu Ψw foliar em condições de falta de água