by Edwina Po Sau Man. / The "0" & "1" in the title are subscripts. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 81-86). / Abstract --- p.II / Acknowledgment --- p.IV / Abbreviations --- p.V / List of Tables --- p.VIII / List of Figures --- p.IX / Table of Contents --- p.XII / Chapter Section 1 --- Introduction --- p.1 / Chapter 1.1 --- Photosynthesis --- p.1 / Chapter 1.2 --- Site of Photosynthesis --- p.3 / Chapter 1.3 --- The Structure of ATPase --- p.6 / Chapter 1.3.1 --- Functions of the Subunits of CF1 --- p.9 / Chapter 1.3.1.1 --- The ε - Subunit --- p.9 / Chapter 1.3.1.2 --- The δ - Subunit --- p.9 / Chapter 1.3.1.3 --- The γ- Subunit --- p.10 / Chapter 1.3.1.4 --- The α- and β- Subunits --- p.10 / Chapter 1.4 --- "Photosynthetic Electron Transport, Δ pH and Phosphorylation inside Chloroplasts" --- p.12 / Chapter 1.5 --- Pesticides --- p.16 / Chapter 1.5.1 --- Paraquat --- p.17 / Chapter 1.5.2 --- Carbamates --- p.20 / Chapter 1.6 --- Objectives of the Study --- p.21 / Chapter Section 2 --- Materials and Methods --- p.22 / Chapter 2.1 --- Apparatus --- p.22 / Chapter 2.2 --- Materials --- p.24 / Chapter 2.2.1 --- Reagents and Buffers for assay of Proton Transport --- p.25 / Chapter 2.2.2 --- Pesticides --- p.26 / Chapter 2.2.3 --- Buffers for SDS-PAGE --- p.27 / Chapter 2.2.4 --- Reagents of Bradford Protein Assay --- p.31 / Chapter 2.3 --- Methods --- p.32 / Chapter 2.3.1 --- Determination of ChlorophyllContent --- p.32 / Chapter 2.3.2 --- Determination of Protein Content in Chloroplast Thylakoids --- p.33 / Chapter 2.3.3 --- Measurement of Proton Transport --- p.34 / Chapter 2.3.3.1 --- Pesticide Concentration Study --- p.36 / Chapter 2.3.3.2 --- Time Course Study --- p.36 / Chapter 2.3.3.3 --- Kinetic Analysis of the Effects of Pesticides on Chloroplast Thylakoids Before and After Illumination --- p.37 / Chapter 2.3.3.4 --- Study of the Combined Effects of Two Pesticides --- p.37 / Chapter 2.3.4 --- Effect of Pesticides on Chloroplast Membranes by SDS-PAGE --- p.38 / Chapter Section 3 --- Results --- p.39 / Chapter 3.1 --- Pesticide Concentration Study --- p.39 / Chapter 3.1.1 --- Paraquat Dichloride --- p.39 / Chapter 3.1.2 --- Methyl Carbamate --- p.41 / Chapter 3.1.3 --- Ethyl Carbamate --- p.43 / Chapter 3.1.4 --- Pyridinol Carbamate --- p.45 / Chapter 3.1.5 --- Pyrrolidinedithiocarbamate --- p.47 / Chapter 3.1.6 --- Diethyldithiocarbamic Acid --- p.49 / Chapter 3.1.7 --- Summary of the Pesticides Concentration Study --- p.51 / Chapter 3.2 --- Time-course Study --- p.52 / Chapter 3.3 --- Kinetic Analysis of the Effects of Pesticides on Chloroplast Thylakoids Before and After Illumination --- p.53 / Chapter 3.3.1 --- Paraquat Dichloride --- p.53 / Chapter 3.3.2 --- Methyl Carbamate --- p.56 / Chapter 3.3.3 --- Ethyl Carbamate --- p.57 / Chapter 3.3.4 --- Pyridinol Carbamate --- p.58 / Chapter 3.3.5 --- Pyrrolidinedithiocarbamate --- p.59 / Chapter 3.3.6 --- Diethyldithiocarbamic Acid --- p.60 / Chapter 3.4 --- Combined Effects of Paraquat and Carbamates --- p.61 / Chapter 3.4.1 --- Paraquat and Methyl Carbamate --- p.61 / Chapter 3.4.2 --- Paraquat and Ethyl Carbamate --- p.64 / Chapter 3.4.3 --- Paraquat and Pyridinol Carbamate --- p.66 / Chapter 3.4.4 --- Paraquat and Pyrrolidinedithiocarbamate --- p.69 / Chapter 3.4.5 --- Paraquat and Diethyldithiocarbamic Acid --- p.71 / Chapter 3.5 --- Gel Electrophoresis --- p.73 / Chapter Section 4 --- Discussion --- p.75 / Chapter Section 5 --- Conclusion --- p.80 / Chapter Section 6 --- References --- p.81 / References --- p.81 / Appendix I Kinetic Analysis of Pesticides with Chloroplast Thylakoids upon Illumination --- p.87 / Appendix II Kinetic Analysis of Pesticides with Chloroplast Thylakoids in the Dark --- p.88 / Appendix III The Initial Rate of Proton Transport in Chloroplast Thylakoids with Different Pesticides --- p.89 / Appendix IV The Conversion of Equivalent Protons from pH Changes --- p.90 / Appendix V Calculation of Proton Transport (%) --- p.91 / Appendix VI Determination of Protein Content in Chloroplast Thylakoids --- p.92 / Appendix VII Calculaiton of Relative Mobility (Rf) --- p.93

Made available in DSpace on 2014-06-11T19:31:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-27Bitstream added on 2014-06-13T18:41:25Z : No. of bitstreams: 1 klein_j_dr_botib.pdf: 464105 bytes, checksum: a5a7f19019acd7bf085f6e55562af753 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A luz pode ser considerada um dos principais fatores ambientais no controle da germinação e desenvolvimento de diferentes espécies, principalmente em plantas nativas. Tendo em vista a importância da espécie Peltophorum dubium para a utilização no re-povoamento de áreas degradadas, arborização e paisagismo, avaliou-se o comportamento fisiológico de suas sementes analisando a influência da luz eo efeito de um protetor físico com diferentes filtros no processo germinativo, emergência, crescimento inicial e trocas gasosas de suas plântulas. Para tanto, frutos maduros de canafístula foram coletadas em diversas matrizes em setembro de 2007. Após a coleta, os frutos foram levados para o Laboratório de Interações Tróficas do Departamento de Botânica do Instituto de Biociência da Unesp/Botucatu onde foram beneficiadas e escarificadas. Desta forma, instalou-se os seguintes tratamentos: T 1- gerbox transparente; T2- gerbox transparente + celofane transparente; T3- gerbox preto; T4- gerbox preto + celofane transparente; T5- gerbox transparente + celofane azul e T6- gerbox transparente + celofane vermelho. Foram avaliadas as seguintes características: porcentagem de germinação, IVG, comprimentos de radícula, de epicótilo, de cotilédone e da plântula, massa seca, clorofilas a, b, totais e relação a/b. Em um segundo experimento realizado na área aberta do Departamento de Botânica (22° 52' de latitude, 48 ° 26' de longitude), no Instituto de Biociências, Unesp, Botucatu - SP, utilizando-se um protetor físico constituido por garrafas do tipo P.E.T. (Polietileno Teraftalato) com volume de 2500 mL sem fundo e sem tampa. Diferentes comprimentos de ondas luminosas foram obtidos acoplando as garrafas do tipo P.ET. com duas camadas de papel celofane com diferentes tonalidades (transparente, azul e vermelho). Desta forma, obtiveram-se os seguintes tratamentos: T1, ausência... / Light is considered one of the major environmental factors controlling the germination and development of different species, mainly native ones. Based on the importance of the species Peltophorum dubium for revegetation of degraded areas, tree planting and landscaping, this study evaluated germination, emergence, initial growth and gas exchanges of canafistula seedlings under light influence by using physical protectors presenting different filters. Thus, the following treatments were adopted: T1, transparent germination box; T2, transparent germination box + transparent cellophane; T3, black germination box; T4, black germination box + transparent cellophane; T5, transparent germination box + blue cellophane; T6, transparent germination box + red cellophane. The evaluated characteristics were: germination percentage, germination velocity index (GVI), radicle, epicotyl, cotyledon and seedling ngth, dry matter, total chlorophylls and their fractions a and b, and the ratio a/b. A second experiment was carried out in an open area from the Department of Botany (22° 52' S, 48 ° 26' W), Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu, Sao Paulo State, Brazil, in which physical protectors corresponding to polyethylene terephthalate (PET)-type bottles (2500 mL) without lid and bottom were used. Different wavelengths were obtained when two layers of cellophane paper of different colors (transparent, blue and red) were added to the PET-type bottles. Thus, the following treatments ere established: T1, absence of physical protector (APP); T2, transparent physical protector (TPP); T3, transparent physical protector + blue cellophane (BPP); and T4, transparent physical protector + red cellophane (RPP). The experimental design was completely randomized, with 4 treatments x 6 evaluation times and 5 replicates. Emergence velocity index (EVI), seedling emergence, survival... (Complete abstract click electronic access below)

Orientador: Arthur Bernardes Cecílio Filho / Coorientador: Priscila Lupino Gratão / Coorientador: Hilário Júnior de Almeida / Banca: André Rodrigues dos Reis / Banca: Rogério Falleiros Carvalho / Banca: Jairo Osvaldo Cazetta / Banca: Roberto Botelho Ferraz Branco / Resumo: O selênio (Se) é um elemento essencial para os seres humanos, no entanto, em plantas é considerado benéfico. O Se pode atuar como antioxidante de células vegetais, melhorando o crescimento das plantas. A aplicação de Se em culturas para fins de biofortificação tem sido uma estratégia eficaz para aumentar o fornecimento do elemento na dieta da população. Entretanto, para ter sucesso é fundamental estudar a aplicação de Se, conhecendo a fonte e concentração adequadas, de forma que não prejudique o crescimento, os aspectos nutricionais, bioquímicos e produtivos da planta. Assim, objetivou-se avaliar o efeito de fontes e concentrações de Se na biofortificação e aspectos nutricionais, fisiológicos e enzimáticos de plantas de couve-flor. O estudo foi realizado em ambiente protegido, com plantas de couve-flor cultivadas em sistema hidropônico, sob concentrações de Se (0, 5, 15, 30 e 60 μmol L-1) nas fontes selenato e selenito de sódio. Os tratamentos foram organizados em delineamento inteiramente casualizado, em esquema fatorial 5 x 2, com quatro repetições. Verificou-se que a aplicação de Se na concentração de 5 μmol L-1 na solução nutritiva promoveu crescimento das plantas e teor do elemento na inflorescência da couve-flor foi superior ao limite considerado adequado pelo Codex Alimentarius. O fornecimento de Se, na fonte selenato, pode ter contribuído para inibir a peroxidação lipídica e a produção de espécies reativas de oxigênio, uma vez que com esse elemento houve melhora na ta... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Selenium (Se) is an essential element for humans, however, in plants is considered beneficial. The Se can act as an antioxidant of plant cells, improving plant growth. The application of Se in crops for biofortification has been an effective strategy to increase the supply of the element in the diet of the population. However, to be successful, it is essential to study the application of Se, knowing the proper source and concentration, so as not to harm the growth, nutritional, biochemical and productive aspects of the plant. Thus, objective was evaluate the effect of sources and concentrations of Se on biofortification and nutritional, physiological and enzymatic aspects of cauliflower plants. The study was carried out in a protected environment, with cauliflower plants cultivated in a hydroponic system, under concentrations of Se (0, 5, 15, 30 and 60 μmol L-1 ) in sources selenate and selenite sodium. The treatments were organized in a completely randomized design, in factorial scheme 5 x 2, with four replications. It was verified that the application of Se at the concentration of 5 μmol L-1 in the nutritive solution promoted plant growth and element content in the cauliflower inflorescence was higher than the limit considered adequate by the Codex Alimentarius. The supply of exits at the selenate source may have contributed to inhibit a lipid peroxidation and a production of reactive oxygen species, since this element is an improvement in the rate of photosynthesis and the regulation of the enzymatic activity of plants. At high concentrations, if supplied mainly in the selenite source, it adversely affects the nutritional balance of plants and, consequently, the growth, the physiological, enzymatic and productive aspects of the cauliflower, depreciating a quality of the product. / Doutor

My dissertation focuses on genome and functional evolution of photosynthetic eukaryotes and the design and implementation of computational methods and tools to enable genome-wide studies to investigate these taxa. The work described here is grouped into two major topics, 1) endosymbiosis and genome evolution, and 2) harmful algal blooms. I discuss my work related to endosymbiosis and genome evolution in chapters 2-4. Chapters 5-6 cover the work related to harmful algal blooms. In chapter 1, I introduce the state-of-art of what is known about the history of plastids and evolution of photosynthesis in eukaryotes, an overview of marine harmful algae, and the specific aims of my dissertation. In chapter 2, I describe the design and implementation of the phylogenetic sorting tool, PhyloSort and the assembly of a high-throughput phylogenomic pipeline. Together, PhyloSort and the pipeline has become a key tool for multiple subsequent studies. chapter 2 also presents a case study using these tools in which we provide an estimate of the number of cyanobacterial genes that have been transferred to the nuclear genome of Plantae through primary endosymbiotic gene transfer; I use the model unicellular green alga Chlamydomonas reinhardtii for this purpose. In chapter 3, I discuss another case of prokaryotic contribution to the nucleus of photosynthetic eukaryotes. Here, the intriguing relationship of Chlamydiae-like bacteria and plants and algae is examined in a large-scale analysis, in which we scanned all available genomes of the primary photosynthetic organisms for genes of potential Chlamydiae origin. Surprisingly, we identified more than fifty Chlamydiae-derived genes in plants and algae. Here, we propose a model for the role that a Chlamydiae-like symbiont might have played in the establishment of the primary plastid in the common ancestor of Plantae. In chapter 4, I describe a study in which we explored the complete protein models of two diatom organisms as representative for photosynthetic chromalveolates and looked for genes that might have been acquired through endosymbiotic (secondary) or horizontal transfers from red or green algae. In contradiction of the “chromalveolate hypothesis” which states that photosynthesis in chromalveolates originated via the engulfment of a red alga symbiont, our study shows an unexpected green algal contribution that is fourfold greater than that of the canonical red algal symbiont. Our data suggest that the chromalveolate history includes a previously unrecognized green algal endosymbiont that was captured and lost prior to the more recent establishment of the red alga plastid, which is widespread in extant photosynthetic chromalveolates. In chapter 5, I discuss the identification of the phylogenetic origin of the genes involved in the biosynthetic pathway of saxitoxin in cyanobacteria. Here, we used a pyrosequencing approach to sequence de novo genomes of two strains of Anabaena circinalis, one of which is saxitoxin-producing and the other is non-toxic. Using comparative and phylogenetic analyses, I show that, within the saxitoxin gene cluster, genes that encode the key and unique enzymes in the pathway are of foreign origin that originated via horizontal transfer from non-cyanobacterial sources. These genes introduced the ability to produce saxitoxin in the ancestor of the toxic cyanobacterial clade. In chapter 6, I describe a gene expression study in which we used massively parallel signature sequencing (MPSS) to investigate RNA abundance patterns in the toxic dinoflagellate Alexandrium tamarense. This work provides the first clear evidence for the utilization by dinoflagellates of transcriptional to regulation. Moreover, using MPSS, we provide an estimate of the number of the distinct genes in Alexandrium tamarense; i.e., remarkably 40,000 loci. Taken together, our data indicate that dinoflagellates possess a great metabolic flexibility that allows them to efficiently toggle between photoautotrophy and heterotrophy based on the environmental conditions.

As maize plants undergo vegetative phase change, they both exhibit heteroblasty, an abrupt change in pattern of leaf morphogenesis, and gain the ability to produce flowers. Both processes are under the control of microRNA 156, whose levels decline at the end of the juvenile phase. Gain of ability to flower is conferred by expression of miR156 targets that encode Squamosa Promoter-Binding (SBP) transcription factors, which in turn induce the expression of MADS-box transcription factors that promote maturation and flowering. What gene expression differences underlie heteroblasty, as well as what causes the reduction in miR156 levels, remain open questions. Here, we compare the gene expression in primordia that will develop into juvenile or adult leaves to identify genes that define these two developmental states and may influence vegetative phase change. In comparisons among successive leaves at the same developmental stage of plastochron 6, three-fourths of approximately 1,100 differentially expressed genes were more highly expressed in juvenile primordia. This juvenile set was enriched in photosynthetic genes, particularly those associated with cyclic electron flow at photosystem I, and genes involved in oxidative stress and retrograde redox signaling. Pathogen responsive pathways including jasmonic acid, salicylic acid, and benzoxazinoids were also up-regulated in juvenile primordia and indeed, we found that exogenous application of jasmonic acid, and hydrogen peroxide delays vegetative phase change in maize seedlings. These results suggest that the timing of vegetative phase change in maize is coordinated in part downstream of photo-oxidative stress signaling. Photo-oxidative stress during greening likely amplifies heterotrophic energy insufficiency. The successful amelioration of these stress signals may ultimately determine the duration of miR156-mediated juvenility.

No description available.

Obligate shade plants possess adaptations that enable them to photosynthesise in the low light environment of the forest floor. Adaptations that facilitate light scavenging may compromise capacity for high rates of photosynthesis. This study compares the responses of obligate shade and facultative shade plant species upon exposure to elevated light. The obligate shade plants were two commercially grown medicinal herb species of ginseng, Panax ginseng C.A. Meyer and Panax quinquefolius L.; and goldenseal - Hydrastis canadensis L. Comparison was made to Arabidopsis thaliana and Pisum sativum L. as facultative shade species. Panax ginseng (Korean ginseng) and Panax quinquefolius (American ginseng) are obligate shade plants found in broadleaf forests of Eastern Asia and North America, respectively. Studies on these plants have shown optimal growth at light intensities between 200-300 [mu]mol photons. m⁻�. s⁻�, or 10-15% of full sunlight, and at intensities greater than 500 [mu]mol photons. m⁻�. s⁻� characteristic photoinbibitory symptoms develop. An atypical response to methyl viologen in photosynthetic electron transport assays was observed in ginseng in both isolated thylakoid membranes and whole leaves. No correlation was found between detectable superoxide dismutase activity and altered methyl viologen reactions. In a mutagenesis study using the model cyanobacterium Synechocystis sp. PCC 6803, a unique amino acid residue in the terminal electron acceptor PsaC, found only in ginseng, was changed and found to have no effect on methyl viologen reactions. Electron transfer to methyl viologen was examined in both isolated thylakoid membranes and whole leaves using chlorophyll a fluorescence and the apparent ability for methyl viologen to act as an electron acceptor was observed to differ between ginseng species. Obligate shade species were observed to possess alternate pools of photosystem II centres that potentially provide a mechanism to maximise photosynthetic gain under low light and during short periods of increased illumination. In experiments designed to identify physiological processes that contribute to increased susceptibility to photoinhibition in obligate shade plants, responses were observed and characterised following a moderate increase in illumination (140 to 400 [mu]mol photons. m⁻� . s⁻�) using chlorophyll a fluorescence induction curve analysis. The obligate shade species exhibited varied responses to elevated light and showed increased susceptibility, to photoinhibition. Photoprotective non-photochemical dissipative capacity was quantified and found to be comparable between all species studied.

Includes bibliographical references. / 1 v. in various pagings : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Sc.)--University of Adelaide, Dept. of Botany, 1994

In higher plants oxygenic photosynthesis primarily takes place in the chloroplasts of leaves. Within the chloroplasts is an intricate membrane system, the thylakoid membrane, which is the site of light harvesting and photosynthetic electron transport. Enclosed by this membrane is the lumen space, which initially was believed to only contain a few proteins, but now is known to house a distinct set of >50 proteins, many for which there is still no proposed function. The work presented in this thesis is focused on understanding the functions of the proteins in the lumen space. Using proteomic methods, we investigated first the regulation of lumenal proteins by light and secondly by dithiol-disulphide exchange, mediated by the disulphide reductase protein thioredoxin. We furthermore performed structural and functional studies of the lumenal pentapeptide repeat proteins and of the PsbP-domain protein PPD6. When studying the diurnal expression pattern of the lumen proteins, using difference gel electrophoresis, we observed an increased abundance of fifteen lumen protein in light-adapted Arabidopsis thaliana plants. Among these proteins were subunits of the oxygen evolving complex, plastocyanin and proteins of unknown function. In our analysis of putative lumenal targets of thioredoxin, we identified nineteen proteins, constituting more than 40 % of the lumen proteins observable by our methods. A subset of these putative target proteins were selected for further studies, including structure determination by x-ray crystallography. The crystal structure of the pentapeptide repeat protein TL15 was solved to 1.3 Å resolution and further biochemical characterization suggested that it may function as a novel type of redox regulated molecular chaperone in the lumen. PPD6, a member of the PsbP-family of proteins, which is unique in that it possesses a conserved disulphide bond not found in any other PsbP-family protein, was also expressed, purified and crystallized. A preliminary x-ray analysis suggests that PPD6 exists as a dimer in the crystalline state and binds zinc ions. The high representation of targets of thioredoxin among the lumen proteins, along with the characterization of the pentapeptide repeat protein family, implies that dithiol-disulphide exchange reactions play an important role in the thylakoid lumen of higher plants, regulating processes such as photoprotection, protein turnover and protein folding.

Global modeling of gross primary production (GPP) is a critical component of climate change research. On local scales, GPP can be assessed from measuring CO₂ exchange above the plant canopy using tower-based eddy covariance (EC) systems. The limited footprint inherent to this method however, restricts observations to relatively few discrete areas making continuous predictions of global CO₂ fluxes difficult. Recently, the advent of high resolution optical remote sensing devices has offered new possibilities to address some of the scaling issues related to GPP using remote sensing. One key component for inferring GPP spectrally is the efficiency (ε) with which plants can use absorbed photosynthetically active radiation to produce biomass. While recent years have seen progress in measuring ε using the photochemical reflectance index (PRI), little is known about the temporal and spatial requirements for up-scaling these findings continuously throughout the landscape. Satellite observations of canopy reflectance are subject to view and illumination effects induced by the bi-directional reflectance distribution function(BRDF) which can confound the desired PRI signal. Further uncertainties include dependencies of PRI on canopy structure, understorey, species composition and leaf pigment concentration. The objective of this research was to investigate the effects of these factors on PRI to facilitate the modeling of GPP in a continuous fashion. Canopy spectra were sampled over a one-year period using an automated tower-based, multi-angular spectroradiometer platform (AMSPEC), designed to sample high spectral resolution data. The wide range of illumination and viewing geometries seen by the instrument permitted comprehensive modeling of the BRDF. Isolation of physiologically induced changes in PRI yielded a high correlation (r²=0.82, p<0.05) to EC-measured ε, thereby demonstrating the capability of PRI to model ε throughout the year. The results were extrapolated to the landscape scale using airborne laser-scanning (light detection and ranging, LiDAR) and high correlations were found between remotely-sensed and EC-measured GPP (r²>0.79, p<0.05). Permanently established tower-based canopy reflectance measurements are helpful for ongoing research aimed at up-scaling ε to landscape and global scales and facilitate a better understanding of physiological cycles of vegetation and serve as a calibration tool for broader band satellite observations.