Made available in DSpace on 2014-06-11T19:30:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02Bitstream added on 2014-06-13T21:01:43Z : No. of bitstreams: 1 pinto_am_dr_rcla.pdf: 291102 bytes, checksum: fd37e45ac3f35881070a810a19d57f4a (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Esta pesquisa teve como objetivo gerar informações básicas sobre a silvicultura das espécies florestais para possibilitar a implementação de programas de reflorestamento e recuperação de áreas degradadas na região amazônica. Trata-se de um estudo fenológico realizado pelo INPA, Manaus, Amazonas, especificamente pela Coordenação de Pesquisas em Silvicultura Tropical, ao longo de 35 anos. Este estudo analisou duas áreas de floresta amazônica, a Reserva Florestal Ducke (RFD) e a Estação Experimental de Silvicultura Tropical (EEST), no período de 1974 a 2000. O objetivo específico foi comparar os padrões fenológicos nas duas áreas experimentais, verificando sua regularidade e relação com fatores climáticos. As espécies selecionadas foram aquelas indicadas com potencial oleaginoso e ecológico, em avaliações preliminares e que estão sendo observadas para o estudo, a saber: Andiroba - Carapa guianensis Aubl.; Cumaru - Dipteryx odorata (Aubl.) Willd.; Casca preciosa - Aniba canelilla (H.B.K.) Mez e Pau rosa - Aniba rosaeodora Ducke. Foram amostrados 21 indivíduos de A. rosaeodora Ducke na RFD e cinco na EEST, e cinco indivíduos das espécies restantes em cada uma das duas áreas de estudo. Observados mensalmente com auxílio de um binóculo para o registro das fenofases (botões florais, antese, frutos imaturos e maduros). Os padrões fenológicos reprodutivos foram descritos de acordo com sua freqüência... . / This research aims to generate basic information about the silviculture of forest species to make the implementation of reforestation programs and the recovering of degraded areas in the Amazon region possible. This phenological research has been conducted by INPA, specifically by the Tropical Silviculture Research Coordination, over a period of 35 years. This study will analyze two areas in the Amazon Forest, Reserva Florestal Ducke (RFD) and Estação Experimental de Silvicultura Tropical (EEST), in the period between 1974 and 2000. The specific objective is to compare the phenological patterns in both experimental areas, verifying their regularity and relationship with climatic factors. The species selected were those indicated with oily and ecological potential in preliminary evaluations: Andiroba - Carapa guianensis Aubl; Cumaru - Dipteryx odorata (Aubl) Willd; Casca preciosa - Aniba canelilla (H.B.K.) Mez and Pau rosa - Aniba rosaeodora Ducke. It were sampled twentyone individuals of A. rosaeodora Ducke in RFD and five in EEST, and five individuals of the remaining species in each one of the two areas of study. The individuals were monthly observed with the assistance of binoculars to record the phenophases. The phenological patterns will be described with regards to their frequency, regularity and duration. The relations among the phenological data with the climatic variables were made through the non-parametric Spearman linear correlation analyses taking in consideration the climatic monthly mean values. It was observed at EEST, that the flowering of the species studied tend to occur in a period of less precipitation, except for Carapa guianensis that tended to bloom in the transition from dry season to rainy season. Whereas, for Aniba rosaeodora the flowering tended to occur in the rainy epoch and... (Complete abstract, click electronic address below).

Made available in DSpace on 2014-06-11T19:30:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-10-25Bitstream added on 2014-06-13T20:21:30Z : No. of bitstreams: 1 alberti_lf_dr_rcla.pdf: 1362214 bytes, checksum: 9ba6f4be07cb47f723a731eb9d4a912a (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Comparação entre borda antrópica, clareiras naturais e o interior da floresta quanto à fenologia de árvores na floresta semidecídua e quanto à fenologia do arbusto Psychotria nuda na Floresta Atlântica). O objetivo da presente tese foi verificar se: (a) nos fragmentos do Morro do Elefante (400 ha, grande), Morro do Cerrito (20 ha, pequeno) e Morro Tabor (15 ha, pequeno) localizados em Santa Maria - RS (29°43'S e 53°47'W), grupos de posições de copa dominantes, co-dominantes, dominadas e oprimidas diferem quanto à intensidade das fenofases botões florais, antese, frutos imaturos e maduros (fenofases reprodutivas); (b) os três fragmentos diferem entre si quanto à intensidade das fenofases reprodutivas, sem considerar e considerando a densidade populacional das espécies. Uma vez que os morros do Cerrito e Tabor não diferiram significativamente quanto à intensidade das fenofases reprodutivas de suas árvores os mesmos foram tratados como um único fragmento (fragmento pequeno) nos capítulos seguintes (c em diante); (c) no fragmento pequeno, borda antrópica e interior da floresta diferem quanto à luz incidente e às variáveis reprodutivas número de flores, número de frutos, taxa de conversão de flores em frutos (sucesso reprodutivo) e tamanho de frutos de Myrocarpus frondosus; (d) na borda e no interior da floresta, há relação entre as variáveis reprodutivas e entre estas com as variáveis individuais altura, índice de esbelteza (circunferência a altura do peito/altura) e distância entre indivíduos de M. frondosus; (e) borda e interior da floresta diferem quanto à luz incidente e às variáveis reprodutivas em indivíduos de Nectandra megapotamica nos fragmentos grande e pequeno; (f) no fragmento pequeno, uma trilha clara difere de uma trilha escura quanto à luz incidente e às variáveis reprodutivas medidas... / Comparison of anthropogenic edge, natural gaps and the forest interior in relation to tree phenology in the semideciduous forest and in relation to the phenology of the shrub Psychotria nuda in the Atlantic forest). The present thesis aimed to verify if: (a) in the forest fragments of Morro do Elefante (400 ha, large), Morro do Cerrito (20 ha, small) and Morro Tabor (15 ha, small) located in Santa Maria - RS (29°43'S and 53°47'W), the dominants, co-dominants, dominated and oppressed canopy position groups differ in relation the intensity of phenophases flower buds, anthesis, immature and mature fruits (reproductive phenophases); (b) the three fragments differ one from another concerning the intensity of phenophase, considering and not considering the population size of species. Since the Morro Cerrito and Morro Tabor did not differ about the intensity of reproductive phenophases of their trees both fragments were considered a single one fragment (small fragment) in the following chapters (c and so on); (c) in the small fragment, there was a difference between edge and forest interior with respect to the light intensity and the reproductive variables number of flowers, number of fruits, ratio of conversion of flowers into fruits (reproductive success) and fruit size of Myrocarpus frondosus; (d) in the edge and forest interior, are the reproductive variables of M. frondosus related to one another and to the individual variables height, slenderness index (height/circumference at breast height), and distance between trees; (e) in the large and small fragments, edge and forest interior differ concerning light intensity and reproductive variables of Nectandra megapotamica individuals; (f) in the small fragment, a lighter trail differ from a darker one concerning the light intensity and reproductive variables measured in the canopy of Gymnanthes concolor individuals... (Complete abstract click electronic access below)

Heme-activated proteins (HAPs) are transcription factors that have multiple roles in plant growth and development, such as embryogenesis, flowering time control, and drought tolerance. In the present study I found that HAP3b was also involved in controlling response to cold stress. Transcript profiling and gene expression analyses indicated that HAP3b repressed the CBF3 regulon under normal growth conditions. As a result, plants with HAP3b-overexpressed showed decreased survival rates while plants homozygous for the null allele hap3b showed an improved freezing tolerance compared to wild-type plants. To understand the mechanism of HAP3b in Arabidopsis, i.e. whether it also acts through forming a heterotrimer, the yeast two-hybrid system and the protein coimmunoprecipitation method were used to identify the proteins that could interact with HAP3b. From yeast two-hybrid analyses, it was found that HAP3b could interact with one (At3g14020) of ten HAP2s and all ten HAP5s tested. Further analyses showed that the newly identified HAP2 protein could only interact with two HAP5 proteins, those encoded by At5g63470 and At1g56170. To address whether HAPs also play important roles in major crop plants, HAP3 genes in barley (Hordeum vulgare L.) were identified and characterized. From database sequence analyses, cloning, and sequencing, it was found that barley plants have at least six full-length members in the HAP3 family. Phylogenetic analyses showed that each barley HAP3 was different, forming its own cluster with the HAP3s from other plant species. Each barley HAP3 also showed its own expression pattern in different tissues, at different developmental stages and under various environmental stresses. In particular, TC176294 showed the highest sequence similarity to HAP3b in Arabidopsis and its high expression was associated with flowering. In addition, TC176294 was upregulated by various abiotic stresses and by abscisic acid (ABA). Thus, TC176294 might be a barley ortholog of HAP3b. TC191694 showed the highest sequence similarity to HAP3c and might be a barley ortholog of HAP3c. TC191694 overexpression plants were early flowering compared to HAP3b-overexpression and wild-type plants while overexpression of TC176294 plants were not.

Successful reproduction in plants is a highly-regulated process reliant on the integration of both endogenous and external cues. Different accessions of the model plant Arabidopsis thaliana have been collected, including those with a winter annual or rapid-cycling flowering habit. Natural variation and mutant screens have enabled many flowering time genes to be identified. A key regulator of flowering is FLOWERING LOCUS C (FLC). FLC is a repressor of flowering and is regulated by a number of genes, including those in the autonomous and FRIGIDA-mediated pathways. Of particular interest are FRIGIDA (FRI) and FRIGIDA-LIKE 1 (FRL1) and the autonomous pathway members, FCA and FY. FRI and FRL 1 promote FLC expression making them dominant repressors of flowering. FRI is proposed to initiate chromatin remodelling at the FLC locus leading to increased FLC expression. Once elevated, FLC levels are maintained until plants undergo an extended period of cold, therefore flowering occurs in spring. In contrast, FCA and FY promote flowering by repressing FLC expression. FCA has also been identified as a receptor of the plant hormone abscisic acid (ABA). Upon binding to FCA, ABA is proposed to disrupt/inhibit the FCA:FY interaction which results in delayed flowering. To characterise the FCA:ABA interaction and identify the ABA binding site, a number of truncated FCA proteins were utilised. Initially a FCA:FY GST-pulldown was used to identify the ABA binding site. However, when ABA failed to inhibit the FCA:FY interaction a direct binding assay using [�H]-ABA was employed. Another Arabidopsis ABA receptor, G-protein coupled receptor 2 (GCR2), was used as a positive control in these binding assays. Both FCA and GCR2 failed to bind [�H]-ABA suggesting a broader issue with the binding assay. The identification of FCA and GCR2 as ABA receptors can be attributed to the quality of the protein assayed, the sensitivity of the binding assay and the subsequent data analysis. This study resulted in the retraction of the original paper (Razem et at, 2006) reporting FCA as an ABA receptor. To investigate the molecular mechanism by which FRI and FRL1 act as positive regulators of FLC expresion, a biochemical approach was taken. FRI and FRL1 have no known homology to any other protein or domain and the only method for assessing protein function is through plant complementation experiments. In the absence of sequence homology, or a timely functional assay, a classical approach was taken to produce soluble protein for analysis. Truncation of predicted regions of disorder and expression, solubility and stability screens produced soluble protein of reasonable purity. This allowed characterisation of the biochemical properties of FRI and FRL1. Interaction studies between FRI and FRL1, and the zinc finger protein SUPRESSOR OF FRIGIDA 4 (SUF4), were also carried out. Polyclonal antibodies against FRI and FRL1, made during this study, were useful for protein detection in these experiments. The interaction studies, together with plant complementation experiments, suggest that the C-terminus of FRI is essential for protein function, while the N-terminus improves FRI activity. These findings provide a better understanding of how the components of the proposed "FRI-complex" may interact to promote FLC expression.

Bibliography: leaves 159-205. This research aims to improve understanding of the control of flowering in relation to photoperiod and temperature to increase knowledge of the floral initiation trigger for Banksia. An exploration of the population biology in relation to genetic variation present in commercial and natural populations of Banksia will provide information on the gene pool for breeding programs. Molecular biology techniques have been used to explore areas such as pollen competition and gene flow.

Discula destructiva, the causal agent of dogwood anthracnose, has caused severe mortality in dogwood over the last 30 years. Although considerable research has been done with dogwood anthracnose, the infection process by D. destructiva is still obscure. A resistant cultivar of Cornus florida, ‘Appalachian Spring’, was discovered and released by the Tennessee Agricultural Experiment Station. However, the resistance mechanisms are unknown. The objectives of this research were 1) to determine the sequence of events in the infection process of D. destructiva in C. florida and 2) to determine how host resistance affects infection events of D. destructiva on flowering dogwood. At 3 days after inoculation (DAI), majority of conidia germinated and hyphae were observed on the leaf surface. Direct penetration by D. destructiva hyphae was observed without appressorium formation. At 8 DAI, hyphae were aggregated between the cuticle and epidermis and grew intracellularly in epidermal cells, palisade parachyma, and spongy mesophyll cells. At 16 DAI, chloroplasts were intact but decompartmentalized and infection sites were clearly defined. Acervuli were detected at 20 DAI and were fully developed at 24 DAI on adaxial and abaxial leaf surfaces. Sporulation (ruptured acervuli) was observed at 20 DAI. This clear understanding of the infection process can be used to look for resistance mechanisms in dogwood germplasm. A resistant line would expect to slow or inhibit one or more infection events. There was no statistical difference between the percentages of germinated conidia on susceptible and resistant cultivars of flowering dogwood one day after inoculation (DAI). However, the resistant cultivar, ‘Appalachian Spring’, significantly suppressed the growth of D. destructiva conidial germ tubes at 2 DAI, 3 DAI and 4 DAI when compared to conidial germ tubes on leaves of the susceptible cultivar ‘Cloud 9’. Observed resistance may be due to smoother wax crystals on adaxial leaf surface and significantly thicker cuticle observed on leaves of ‘Appalachian Spring’. An unknown compound, observed highly concentrated in resistant but lower in susceptible cultivars, may be important as a resistance mechanism. These strategies reduced the inoculum potential of D. destructiva and play important roles in why ‘Appalachian Spring’ is resistant to dogwood anthracnose. These results provide new ways to use conidia germination test and germ tube growth measurement for detecting resistant cultivars.

This thesis describes the characterization of the Arabidopsis thaliana mutant terminal flower2 (tfl2), the cloning of the corresponding gene, and the analysis of TFL2 function in plant development. The tfl2 mutant is pleiotropic, exhibiting early floral induction in both long and short day conditions, a terminating inflorescence and dwarfing. TFL2 was isolated using a positional cloning strategy, and was found to encode a homolog to HETEROCHROMATIN PROTEIN1 (HP1), previously identified in yeast and animals where it is involved in gene regulation at the level of chromatin, as well as in the structural formation of constitutive heterochromatin. Investigating the light response during seedling photomorphogenesis I found that the tfl2 hypocotyl is hypersensitive to red and far-red light and that tfl2 is impaired in phytochrome mediated light responses such as the shade avoidance response. In the tightly regulated transition to flowering, we have shown that tfl2 might contribute to the interpretation of both external signals such as light and temperature as well as endogenous cues, via FCA, in the autonomous pathway. The Arabidopsis inflorescence meristem is indeterminate, and TFL2 possibly acts to maintain this indeterminate fate by repression of the floral meristem genes APETALA1 and AGAMOUS. In yeast two hybrid experiments TFL2 was shown to interact with IAA5, a protein with suggested functions in auxin regulation. Further, in tfl2 mutants the levels of the auxin indole-3-acetic acid decrease with age in aerial tissues, suggesting a function of TFL2 in regulation of auxin homeostasis and response. In summary, TFL2 contributes to regulation of several aspects of plant development, in accordance with the mutant phenotype and the identity of the TFL2 protein.

The plastid genomes of land plants are generally highly conserved in gene content and order, genome organization, and rates of sequence evolution; however, a few groups have experienced genomic change. The previously published sequence of Pelargonium X hortorum (Geraniaceae) reveals the largest, most rearranged plastid genome among land plants, and rate heterogeneity and genomic change have been documented in the monocot family Poaceae. Three initiatives were taken to characterize plastid genome evolution better in these groups. First, I estimate and compare genome-wide rates of sequence evolution in Geraniaceae genes relative to other angiosperms. An analysis of nucleotide substitutions for 72 plastid genes from 47 angiosperms, including nine Geraniaceae, shows that values of dN are accelerated in ribosomal protein and RNA polymerase genes. dN/dS, an indicator of selection, is significantly elevated in the same two classes of genes and ATPase genes. Second, I sequenced three additional Geraniaceae plastid genomes (Erodium texanum, Geranium palmatum, and Monsonia speciosa) and compare these sequences to each other, P. X hortorum, and other rosids. Geraniaceae plastid genomes are highly variable in size, gene content and order, and base composition. The genome of M. speciosa is among the smallest land plant plastid genomes, and one copy of the IR region in E. texanum has been lost. Gene/intron loss and gene duplication are rampant in Geraniaceae plastid genomes, and a number of losses are phylogenetically inconsistent. To explain the unusual rates and patterns of genome evolution in Geraniaceae, I propose a model of aberrant DNA repair coupled with altered gene expression. Lastly, I characterize genome evolution in the family Poaceae and order Poales. There has been a recent surge in the availability of Poaceae sequences, but a comprehensive analysis of genome evolution had not been performed that included any non-grass Poales taxa. I present the sequence of Typha latifolia (Typhaceae), the first non-grass Poales sequenced to date, and I show that Poaceae plastid genomes exhibit increased genomic rearrangements and nucleotide substitutions. These analyses show the extent of lineage-specific rate acceleration on the branch leading to Poaceae and deceleration during the diversification of the family. / text

No description available.

Early flowering is important for maize adaptation to short-season growing environments. Dwarfism, by preventing lodging, has the potential to increase grain yield. This thesis investigates three novel mutants of maize. The early flowering mutant (EarlyF) sheds pollen 1 to 5 days earlier than wild type plants. EarlyF, was shorter and developed fewer leaves than wild type plants, suggesting an earlier transition from vegetative to reproductive development. A candidate QTL for EarlyF maps to bin 7.03. The two allelic dwarf mutants, brachytic3-1 and brachytic3-2, have short internodes at maturity, resulting in severely reduced plant height. Despite being short, days to pollen shed and number of leaves were unchanged for both brachytic3-1 and brachytic3-2. brachytic3 maps to a ~ 7 Megabase region of bin 5.04. This thesis characterizes EarlyF, br3-1 and br3-2 and sets the stage for positionally cloning the mutations causing these mutants and has potential to contribute to maize improvement.