Thesis (Ph. D.)--University of Wisconsin--Madison, 1987. / Typescript. Vita. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Waikato, 2007. / Title from PDF title page (viewed on May 6, 2007). Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:35:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-21Bitstream added on 2014-06-13T20:06:56Z : No. of bitstreams: 1 bertolin_dc_dr_ilha.pdf: 1651986 bytes, checksum: 10399b52ee1922c67368a091e43d8a3b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O Brasil é o maior consumidor per capita de feijão e possui produtividade média de 946 kg ha-1, e dentre as causas da baixa produtividade Nacional está a falta de utilização de sementes de boa qualidade. O nível de qualidade fisiológica de sementes é avaliado por meio dos parâmetros viabilidade e vigor. A tecnologia de sementes como segmento do processo de produção tem procurado melhorar os testes de vigor com o objetivo de aprimorar a estimativa do potencial fisiológico de um lote de sementes em campo. Atendendo aos interesses da tecnologia de sementes o trabalho objetiva o estudo dos testes de alagamento, envelhecimento acelerado e deterioração controlada para avaliação do vigor de sementes de feijão (Phaseolus vulgaris, L.). Para isso foram utilizados 30 genótipos de feijão, sendo que o estudo individual de cada teste foi realizado com 19 genótipos. Para o teste de alagamento foram estudadas variações de períodos de embebição (4, 12, 16, 24 e 30 horas), e quantidades de água (50 e 75mL), para envelhecimento acelerado foram avaliadas variações entre temperaturas (41, 43 e 45°C) e períodos (12, 24, 36, 48 e 60horas) e para deterioração controlada o teste foi realizado com avaliação de períodos (0, 2, 3 e 4 dias), temperaturas (37 e 40°C) e umidades iniciais das sementes (0, 16, 20 e 24%). O estudo foi conduzido no Laboratório de Análise de sementes da Universidade Estadual Paulista, campus de Ilha Solteira-SP, durante o período de março de 2008 a março de 2010. Alguns genótipos apresentam comportamento diferente em relação aos parâmetros envolvidos no teste de envelhecimento acelerado, sendo que este pode ser realizado à 43ºC por 24 horas para determinação do vigor, o teste de alagamento possibilita diferenciar lotes de sementes com qualidade fisiológica distinta quando realizado com 50 ou 75mL de água por 12 horas e é influenciado... / Brazil is the largest per capita consumer of commom beans grains and has an average productivity of 946 kg ha-1, and among the causes of low productivity is the lack of National use of good seeds quality. The level of seed quality is evaluated by the parameters viability and vigor. The seed technology as segment of the production process has sought to improve the vigor tests with objective of improving the estimation of the physiological potential of seeds under field conditions. According to the interests of seed technology this research work objectively study the tests of flooding, accelerated aging and controlled deterioration to assess the vigor of commom bean seeds (Phaseolus vulgaris L.). For that were used 37 genotypes, and individual study of each test was conducted with 20 genotypes. For the test of flooding were studied variations of soaking periods (4, 12, 16, 24 and 30 hours), and the quantities of water (50 and 75mL) accelerated aging were evaluated for variations between temperatures (41, 43 and 45 ° C) and periods (12, 24, 36, 48 and 60horas) and controlled deterioration test was performed with evaluation periods (0, 2, 3 and 4 days), temperatures (37 and 40 ° C) and seed moisture (12, 16, 20 and 24%). The study was conducted at the Laboratório de Análise de Sementes of the Faculdade de Engenharia- Universidade Estadual Paulista, campus of Ilha Solteira-SP during the period 2008/2010. Some genotypes have behavior different regarding the parameters involved in the accelerated aging test, and this can be performed at 43 ° C for 24 hours to determine the vigor level, flooding test allows differentiating seed lots with distinct physiological quality when performed with 75mL of water for 12 hours and is influenced by genotypic characteristics, such as lignin content of seed coat, the controlled deterioration test provides satisfactory results when performed... (Complete abstract click electronic access below)

Orientador: Paulo Mazzafera / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-11T01:13:03Z (GMT). No. of bitstreams: 1 Sobczak_JullyanaCristinaMagalhaesSilvaMoura_M.pdf: 2446892 bytes, checksum: 4c97412103a3d5abdab642b94a070f35 (MD5) Previous issue date: 2008 / Resumo: O controle de deposição de ligninas em diferentes espécies de Eucalyptus foi estudado utilizando baixa temperatura como modulador. Em baixas temperaturas, foi observada redução significativa dos crescimentos foliares de E. camaldulensis, E. grandis e E. pellita e isto pareceu ser um mecanismo adaptativo a este tipo de estresse. Em E. camaldulensis e E. pellita ocorreram reduções significativas dos crescimentos caulinares. Já em E. globulus, foi observado um aumento significativo destes crescimentos, demonstrando existir temperaturas preferenciais para cada espécie que podem estar relacionadas com a distribuição natural das mesmas, bem como com padrões de atividades enzimáticas, expressões gênicas e acúmulo diferencial de ligninas. Foi observada uma atividade diferencial de guaiacol peroxidase (GPX), siringaldazina peroxidase (SPX) e polifenoloxidases (PPO) nas espécies de Eucalyptus expostas às baixas temperaturas. Adicionalmente, foi observado também um padrão de expressão gênica diferenciado para as enzimas envolvidas na biossíntese dos precursores monolignóis das ligninas e variações na deposição de ligninas, indicando haver um efeito dos tratamentos de baixas temperaturas nestes processos. Em E. pellita, as maiores atividades de peroxidases e polifenoloxidases nas regiões apicais das plantas expostas aos tratamentos de baixa temperatura foram acompanhadas de um maior acúmulo de ligninas nessas regiões, bem como de uma redução do crescimento caulinar. Em E. grandis e em E. camaldulensis observou-se que as atividades de peroxidases e polifenoloxidases tendem a ser maiores em baixas temperaturas. Observou-se também uma maior expressão de importantes genes envolvidos na biossíntese dos monolignóis precursores das ligninas, mas isto não foi acompanhado de uma maior deposição de ligninas nestas plantas. Em E. grandis não ocorreram reduções dos crescimentos caulinares em baixas temperaturas, mas em E. camaldulensis as reduções observadas poderiam estar relacionadas como outros fatores, como uma maior degradação de AIA, promovida pelo aumento das atividades de peroxidases. Em E. globulus foram observadas reduções significativas das atividades enzimáticas analisadas, tanto nas amostras de ápices quanto em bases caulinares, expostos às baixas temperaturas. Esta menor atividade enzimática também foi acompanhada de uma menor expressão de genes envolvidos na biossíntese de ligninas. Observou-se uma redução da concentração de ligninas determinadas por ácido tioglicólico nas amostras de ápice e base das plantas expostas às baixas temperaturas e a quantidade de lignina insolúvel e solúvel, determinada pelo método Klason, aumentou nas amostras de ápices. Deste modo, em E. globulus, a maior tendência de redução de ligninas poderia estar associada com o maior crescimento desta espécie em baixas temperaturas. Ao utilizar um estresse como modulador da biossíntese de ligninas, alguns dos genes envolvidos puderam indicar possíveis pontos específicos do metabolismo de ligninas a serem alterados para se produzir plantas melhoradas com menor teor deste polímero / Abstract: The control of lignin deposition in different Eucalyptus species was studied using low temperature as a modulator. Under low temperatures, a significant reduction of leaf growth was observed in E. camaldulensis, E. grandis and E. pellita and this seemed to be an adaptive mechanism to this type of stress. Significant reductions of stem growth were observed for E. camaldulensis and E. pellita. In contrast, a significant increase of stem growth was found for E. globulus, indicating that the optimal growth temperatures for each species might reflect their natural distribution or patterns of enzymatic activities, patterns of gene expression and differential accumulation of lignins. Differential activities of guaiacol peroxidase (GPX), syringaldazine peroxidase (SPX) and polyphenol oxidases (PPO) were observed for the Eucalyptus species exposed to low temperatures. It was also observed that a pattern of differential gene expression exists for the enzymes involved in the biosynthesis of monolignol lignin precursors, as well as variations in lignin deposition, indicating an effect of the low temperature treatments in these processes. The increased peroxidase and polyphenol oxidase activities in the stem apical regions of E. pellita plants exposed to the low temperature treatments were accompanied by an increase in lignin accumulation in these regions. A reduction in stem growth was also found in this species. It was observed that the peroxidase and polyphenol oxidase activities tend to be greater under low temperatures for both E. grandis and E. camaldulensis. Additionally, a transcriptional increase of important genes involved in the biosynthesis of monolignol lignin precursors was found, although this was not accompanied by an increase in lignin deposition in these plants. A reduction in stem growth was not observed at low temperatures for E. grandis but in E. camaldulensis the observed reduction in growth could also be related to others factors, such as a greater degradation of AIA promoted by the increase in the activity of peroxidases. A significant reduction was observed for all of the enzymatic activities analyzed, in both shoot tips and shoot bases of E. globulus plants exposed to low temperature treatments. This lower enzymatic activity was also accompanied by a lower expression of genes involved in lignin biosynthesis. The amount of lignin determined by thioglycollic acid in the samples of shoot tips and shoot bases of the plants exposed to low temperatures was reduced and the amount of acid insoluble and soluble lignin, determined by the method of Klason, increased significantly in the shoot tips. Thus, the tendency of reducing lignin content under cold treatment observed for E. globulus could be associated with its increase in growth at low temperatures. By using a stress as a modulator of lignin biosynthesis, some of the genes involved may indicate possible specific points of lignin metabolism that could be changed when breeding plants for lower content of this polymer / Mestrado / Mestre em Biologia Vegetal

Genom att använda förnyelsebara energikällor som exempelvis träbränslepellets, kan det skapas förutsättningar för en hållbar utveckling. Träpelletsproduktionen ökar globalt och ökningen förväntas fortsätta i framtiden. Det leder i sin tur till att pelletsindustrin måste börja utöka sin råmaterialbas, exempelvis genom att använda biprodukter som bark. För att förbättra pelletsegenskaperna och pelleteringsprocessen kan exempelvis ett additiv användas. Syftet med denna studie var att öka kunskapen om hur lignin och cellulosa som additiv påverkar pelleteringsegenskaperna på pellets producerade av granspån, björkspån och aspbark. Målet var att ta reda på vilka effekter lignin och cellulosa har på pelletsens densitet, hårdhet, fuktupptagning samt energi vad gäller kompression och friktion. Lignin och cellulosa tillsättes som additiv vid halterna 0, 1, 2,5 och 4 % för pelletering av gran- och björkspån samt aspbark i en enpetarpelletspress. Pelletsen producerades med matristemperaturen 120, 100 och 100oC samt fukthalten 12, 10 respektive 14%. För pellets producerade av granspån och aspbark resulterade tillsättningen av lignin i förbättrade pelletsegenskaper, utan att kompressionsenergin och friktionsenergin förändrades. Vad gäller pellets producerade av björkspån, förändrade inte tillsättningen av lignin och cellulosa pelletsegenskaperna, däremot ökade den energin vad gäller kompression och friktion. Både lignin och cellulosa minskade fuktupptagningsförmågan hos pellets. / Using renewable energy sources, such as wood fuel pellets, can create conditions for sustainable development. Wood pellet production is increasing globally and the increase is expected to continue in the future. This means that the pellets industry must start to increase their raw material base, for an example by using by-products as bark. In order to improve the pellet properties and the pelleting process, additive can be used. The purpose of this study was to increase the knowledge of how lignin and cellulose as additives affect pelleting properties on pellets produced from spruce-and birch sawdust and aspen bark. The aim was to find out what effects lignin and cellulose have on the density of the pellets, hardness, moisture absorption, and energy for compression and friction. Lignin and cellulose were tested as additives in the amount of 0, 1, 2.5 and 4% for pelletizing spruce-and birch sawdust as well as aspen bark in a single pellet press. The pellets were produced at a die temperature of 120, 100oC and 100, and a moisture content of 12, 10 and 14%. For pellets produced by spurce sawdust and aspen bark, the addition of lignin resulted in improved pellets, without the compression and friction energy changing. In the case of pellets produced by birch sawdust, the addition of lignin and cellulose did not change the pellet properties, on the other hand, it increased the energy for compression and friction. Both lignin and cellulose reduced the moisture absorption capacity of pellets.

M.Sc. / Inducible defence responses in both a susceptible cotton cultivar ( Acala ) and a resistant cotton cultivar ( OR-19 ) in response to elicitors fromVerticillium dahliae were investigated. These oligosaccharin elicitors represent the heat solubilized, non-dialyzable fraction of the pathogen cell wall. This elicitorfraction consist of 6.57 % protein and 68 % carbohydrate and represent merely a discrete portion of the cell wall. Moreover, symptoms such as chlorosis and necrosis were induced by the elicitor in both cultivars, but the timing and magnitute of symptom development differed in that the symptoms occurred much faster and were more intense ( hypersensitive response) in the resistant cultivar. An effective elicitor concentration of 30 ug/ ml ( = 21 ug glucose equivalents) was determined and used throughout this study. Inducible defence responses i.e, the accumulation of PR-proteins and specifically activities of B-1,3-glucanase and chitinase were investigated in the intercellular environment as well as cellular extractions of both cultivars. An attempt was also made to analyse the expression of B-1 ,3-glucanase and chitinase genes at them RNA level ( level of transcription) and to correlate it to the determined levels of enzyme activities. Lignification as well as smaller plant metabolites i.e, sesquiterpenoid-phytoalexins relating to pathogenesis that are induced by the elicitor, were also investigated in both cultivars. In this study it is shown that differences are found between Acala and OR-19 and that some of these differences can be correlated to plant resistance. These differences found in the time studies ( intensity, time of response, qualitative and quantitative differences ) of the defence responses induced in both cultivars is discussed against the background of disease resistance.

D.Sc. (Biochemistry) / Please refer to full text to view abstract

Lignin is a highly abundant aromatic biopolymer deposited during the final stages of secondary cell wall formation in plants and it constitutes a substantial proportion of the dry weight of woody plant stems. Lignin contributes structural support to xylem cell walls and hydrophobisity to water-conducting vessels and forms a defence mechanism against pathogen invasion. Although being an essential part of normal plant cell development, lignin content and composition are targets for tree improvement, because residual lignin in paper pulp has negative effects on paper quality and lignin therefore has to be removed using treatments that are expensive and often detrimental to the environment. At present, little is known about the amount of allelic diversity in lignin biosynthetic genes and whether such diversity may be associated with variation in lignin content and composition. However, the identification of alleles associated with desirable lignin phenotypes is dependent on a detailed understanding of the molecular evolution and population genetics of these genes. This M.Sc. study was aimed at analysing nucleotide and allelic diversity in two lignin biosynthetic genes of Eucalyptus trees. Additionally, the study aimed to develop single nucleotide polymorphism (SNP) markers that could be used to assay allelic diversity for these genes in populations of two target species, E. grandis and E. smithii. Orthologues of the tobacco LIM-domain1 (NtLIM1) transcription factor gene involved in the regulation of lignin biosynthesis were isolated from E. grandis and E. smithii. Approximately 3 kb of genomic sequence including the promoter and full-length gene regions were isolated for the two orthologues, respectively labeled EgrLIM1 and EsLIM1. The predicted amino acid sequences of EgrLIM1 and EsLIM1 were 99.4% identical to each other and indicated that LIM1 is a small protein of only 188 residues in eucalypt trees and has a predicted molecular weight of 21.0 kDa. Quantitative, real-time RT-PCR analysis confirmed the expression of LIM1 in wood-forming tissues undergoing lignification. Ten putative cis-regulatory elements were observed in the promoter regions of EgrLIM1 and EsLIM1including a GA-dinucleotide microsatellite that appears to be specific to LIM1 promoters of Eucalyptus tree species. The full-length LIM1 gene sequences could subsequently be used in the assessment of nucleotide and allelic diversity, together with the full-length CAD2 sequences that were already available in the public domain. The level of nucleotide and allelic diversity and the distribution and decay of linkage disequilibrium (LD) were surveyed in 5’ and 3’ derived gene fragments of CAD2 and LIM1 obtained from 20 E. grandis and 20 E. smithii individuals. Each gene displayed a unique genetic diversity profile, but for the most part, nucleotide diversity (π) was estimated at approximately 0.0010 except for the E. grandis LIM1 gene where π lower than 0.0040 was observed. Generally, except for the high amounts of LD observed in the CAD2 gene of E. grandis (> 2.5 kb), LD decayed within 500 bp. A large number (13 to 45) of SNP sites (defined as single nucleotide changes with minor allele frequencies of at least 0.10 in each species) were observed in each gene of each species. The high SNP density (ranging from one per 45 to one per 155 bp) observed in the two genes facilitated the efficient development of SNP markers to be used in future aspects of LD mapping, association genetics and marker-assisted breeding. The allele sequences obtained for the CAD2 and LIM1 genes were used as templates for the development of SNP marker panels (a series of six or seven SNP markers analysed together) for the analysis (tagging) of SNP haplotype diversity in species-wide reference populations (100 E. grandis and 137E. smithii individuals) of the two species. Each tag SNP was assayed using a single base extension assay and capillary gel electrophoresis. High polymorphism information content (average PIC of 0.836) was observed for the SNP marker panels. Four SNPs in the CAD2 and two in the LIM1 genes were found to be polymorphic in E. grandis and E. smithii (i.e. trans-specific SNPs), suggesting a possible ancestral origin for these polymorphisms. Assessment of candidate gene variation in the genomes of forest trees is of importance to ultimately be able to predict the amount and structure of nucleotide diversity available for the future design of SNP assays at the whole-genome level. Such assays will be useful to study differentiation among tree species and populations, to associate nucleotide polymorphisms with desirable phenotypes and to increase the efficiency of tree improvement approaches. / Dissertation (MSc (Genetics))--University of Pretoria, 2009. / Genetics / unrestricted

Eucalyptus trees are an important source of wood and fibre. The wood (secondary xylem) of this genus is widely used for pulp and papermaking. However, our understanding of the mechanisms which control the wood formation process (xylogenesis) in Eucalyptus and other woody species is far from complete. One reason is that xylogenesis is a very complex developmental process. The major components of wood are lignin and cellulose. Many genes involved in lignin and cellulose biosynthesis have been characterized. For example, Cinnamoyl CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD) are two important lignin biosynthesis genes. Plant cellulose is synthesized by cellulose synthase enzymes with the aid of some other proteins, such as sucrose synthase (SuSy) and sucrose phosphate synthase (SPS). Another factor which makes it difficult to analyze the function of Eucalyptus wood formation genes in vivo, is the long generation times of Eucalyptus trees and the difficulty to obtain transgenic Eucalyptus plants. Therefore, in this study, we investigated the use of Arabidopsis thaliana as a model system for functional analysis of wood formation genes. We transformed a lignin and a cellulose biosynthesis gene isolated from Eucalyptus to wild-type and mutant genetic backgrounds of Arabidopsis in order to test our ability to modify the cell wall chemistry of Arabidopsis thaliana using tree genes. The Eucalyptus CCR (EUCCR) gene was transformed into wild-type Arabidopsis (Col-0) and irregular xylem 4 (irx4) mutant plants, in which the homolog of EUCCR is mutated. A Eucalyptus cellulose synthase gene (EgCesA1) was also transformed into irregular xylem 1 (irx1) mutant plants, in which the homolog of EgCesA1 is mutated. Transgenics were only obtained from wild-type Col-0 transformed with EUCCR and from irx1 transformed with EgCesA1. We studied the cell wall chemistry of wild-type Arabidopsis plants overexpressing the Eucalyptus CCR gene. Chemical analysis of inflorescence stems revealed the modification of lignin and cellulose content in transgenic plants. Total lignin content was increased in T2 (5%) and T3 (12%) lines as revealed by micro-Klason lignin and thioglycolic acid quantification methods, respectively. High Pressure Liquid Chromatography (HPLC) analysis revealed that cellulose content was significantly decreased (10%) in T2 transgenic plants. This suggested the reallocation of carbon from cellulose to lignin as a result of overexpression of EUCCR in transgenic plants. Interestingly, thioacidolysis analysis revealed that in T2 plants, monomethoxylated guaiacyl (G) monomer was increased (16%) and bimethoxylated syringyl (S) monomer was decreased (21%). Therefore, the S/G lignin monomer ratio was significant decreased (32%). This implied that EUCCR might be specific to G monomer biosynthesis. The results described above confirmed that Arabidopsis thaliana can be used to model the function of wood formation genes isolated from Eucalyptus. Two novel full-length Eucalyptus sucrose synthase (SuSy) genes, EgSuSy1 and EgSuSy3, and one putative pseudogene, EgSuSy2, were also isolated in this study. Degenerate PCR was used to amplify Eucalyptus SuSy fragments from cDNA and genomic DNA. 3’RACE was used to amplify the 3’ ends of two Eucalyptus SuSy genes. Genome walking was performed to obtain the 5’ ends of EgSuSy1 and EgSuSy2 whereas 5’RACE technology was used to isolate the 5’ end of EgSuSy3. However, 3’RACE analysis failed when we tried to identify the 3’ end of EgSuSy2. Sequencing results from the genome walking product of EgSuSy2 further revealed that the start codon of this gene was missing, and we hypothesize that this is a psuedogene in the Eucalyptus genome. The EgSuSy1 cDNA was 2498 bp in length with an open reading frame of 2418 bp encoding 805 amino acids with a predicted molecular mass of 92.3 kDa. The 2528 bp full-length EgSuSy3 cDNA contained the same length of open reading frame as EgSuSy1, but encoded a polypeptide with a predicted molecular mass of 92.8 kDa. The results of quantitative real-time RT-PCR, phylogenetic analysis and gene structure of the two genes revealed that both genes might be involved in cellulose biosynthesis in primary and secondary cell walls of Eucalyptus. These two genes, EgSuSy1 and EgSuSy3, could therefore be useful targets for genetic engineering of wood properties in Eucalyptus. / Dissertation (MSc)--University of Pretoria, 2008. / Genetics / unrestricted

The conflicting problem involving the herds of mule deer (Odocoileus hemionus) are of major interest throughout Utah. Individuals who are affected the most are sportsman, ranchers, fruit growers, sanitation engineers, home owners, federal administrators, and big game managers. Mainly, the problem arise as a result of insufficient forage, especially on the winter range. Here, factors such as increased deer numbers, decreased range productivity, severe winters, and expanded agricultural activity make more acute the problem of a naturally critical season.