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1
Gxaba, Nomagugu. "The effect of exogenous growth regulators on salinity tolerance in Erucastrum strigosum." University of the Western Cape, 2003. http://hdl.handle.net/11394/8268.
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Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol)Randomized block experiments were conducted to examine the putative amelioratory effects of kinetin or gibberellic acid at concentrations (0, 4, 12.5, 40, and 125 μM) in Erucastrum strigosum plants subjected to a salinity series (0, 100, 200, 300, and 400 mM NaCl) in the greenhouse. When the highest salinity concentration (increased stepwise) was reached, growth effects in relation to water and cation content of the plants were evaluated. Growth and water content were reduced progressively with salinity treatments. Na+ concentration accumulated with salinity treatments to levels that were much higher than that of other cations (K+, Ca2+ and Mg2+) in both organs. However, it is noteworthy that Na+ distribution was more in shoots than in roots. In kinetin treated plants, shoot growth decreased whilst root growth increased with moderate hormonal treatments.
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Darwiche, Amal Omar 1964. "Effect of cytokinin, gibberellin, and nitrogen applications on the growth of eldarica pine seedlings." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276979.
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A greenhouse experiment was conducted over a ninety day period to test the effect of different nitrogen fertilizer regimes and several application rates of compounds with gibberellin and cytokinin activity (GA4/7 and BA, respectively) on the growth and development of Pinus brutia var. eldarica. Nitrogen produced no significant effects and this was attributed to its abundance in the potting medium, to begin with. All levels of growth regulators used showed a highly significant effect on vegetative development. A reduction in root collar diameter, shoot elongation, needle nitrogen content and oven-dry weight, was observed, especially when the medium and high hormonal rates were used. Phytotoxicity increased with the increase in concentration of both chemicals. Ba induced a proliferation of adventitious buds along the stem of saplings, but this was accompanied with rapid new top growth and branching at the top only when BA was applied in conjunction with GA4/7.
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Rossouw, Jan Adriaan. "Effect of cytokinin and gibberellin on potato tuber dormancy." Diss., Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-07302008-164519.
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Pound, William Eugene. "The effect of 1,1-dimethylaminosuccinamic acid (B-nine SP) on endogenous gibberellic acids in Chrysanthemum morifolium /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487260859495302.
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Bezuidenhout, Johannes Jacobus. "Elucidating the dual physiological induced effect of gliotoxin on plants / Johannes Jacobus Bezuidenhout." Thesis, North-West University, 2011. http://hdl.handle.net/10394/6945.
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Fungi and Oomycetes represent the two most important groups of eukaryotic plant pathogens. Besides chemical and physical control of these pathogens, biological control is an approach enjoying increasingly more focus. One of the biological agents increasingly employed in biological control of plant pathogenic fungi is ironically the fungus Trichoderma, more specifically Trichoderma harzianum. Besides control of the fungal plant pathogens, another interesting aspect observed when plants are treated with Trichoderma harzianum are effects such as complete and even stand of plants, faster seed germination, increases in plant height and overall enhanced plant growth. Though there have been various studies on this effect, almost no research has yet been conducted to elucidate the mechanism by which these effects occur. In particular, effects such as faster seed germination suggest that Trichoderma harzianum produces a metabolite that may mimic the plant growth hormone gibberellic acid. Through an evaluation of the various metabolites produced by Trichoderma harzianum; gliotoxin seemed structurally most similar to gibberellic acid. To verify that gliotoxin can indeed serve as an analogue for gibberellic acid and elicit similar physiological responses in plants, a two–pronged approach was followed.
Firstly, molecular similarity evaluation through common pharmacophore evaluation was conducted, followed by docking simulations into the recently discovered receptor for gibberellic acid. Common pharmacophore evaluation between gibberellic acid and gliotoxin showed successful alignment of gliotoxin into the gibberellic acid based pharmacophore space. Furthermore, docking simulations further strengthened this by the similarity in docking scores calculated and the similar poses of the ligands (gliotoxin and gibberellic acid) in the receptor space. However, similarity in pharmacophore alignment and docking simulation results only suggest that gliotoxin should be able to occupy the receptor space, but it is not a guarantee that similar physiological responses will be elicited.
In the second part of the project, the ability of gliotoxin to elicit similar physiological responses in plants to gibberellic acid was investigated. For this, a–amylase induction; plant emergence and height; and chlorophyll fluorescence were compared for both gliotoxin and gibberellic acid treatments. In terms of a–amylase induction, gliotoxin was able to induce production of the enzyme as visualised by starch–containing native gel electrophoresis (zymograms). Gliotoxin induced the strongest response at a 10–6 M dilution which is typically the range expected for hormones in biological systems in de–embryonated seeds of Phaseolus vulgaris. Gibberellic acid was able to induce the strongest response at a 10–7 M dilution. In essence, similar physiological responses were observed. In terms of plant emergence and plant height, treatment with gliotoxin or gibberellic acid resulted in plant emergence a day earlier than the untreated control. However, even though there were slight differences in plant height favouring the gliotoxin or gibberellic acid treated plants, the differences were not statistically significant. Thus, in this regard similar responses were again observed for both gliotoxin and gibberellic acid treatments. In the final evaluation the effect of gliotoxin and gibberellic acid treatments on the chlorophyll fluorescence of mature plants was investigated. Overall, both gliotoxin and gibberellic acid elicited beneficial effects on plant vitality, expressed through PI(Abs) with the gliotoxin treatment performing better than the equivalent gibberellic acid treatment.
Overall, the physiological tests demonstrated that gliotoxin can indeed elicit similar positive physiological responses to gibberellic acid in Phaseolus vulgaris. Furthermore the test used in this project can serve as a standard evaluation bench for screening for gibberellic acid analogues on a laboratory scale before larger scale field trials are considered.Thesis (Ph.D. (Microbiology))--North-West University, Potchefstroom Campus, 2012.
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Loaring, Huw W. "Alkylation studies on the gibberellins." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338439.
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Harrison, Polly A. "Partial synthesis of selected gibberellins." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294577.
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Dickson, Ross L. "The effect of water stress, nitrogen and gibberellic acid on the phytotoxicity of post-emergent herbicides to Avena spp." Lincoln University, 1990. http://hdl.handle.net/10182/1283.
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A series of experiments was carried out on cultivated oat (Avena sativa L. cv Amuri) to examine the efficacies of fluazifop-butyl and glyphosate against water stressed plants, plants grown in low and high nitrogen and plants treated with gibberellic acid (GA₃). Avena sativa L. was used as a test plant and on completion of the experiments, further studies were carried out on the weed species wild oat (Avena fatua L.). In the laboratory, plants maintained at wilting point for five days before and nine days after spraying and treated with fluazifop-butyl (0.5 kg a.i./ha) appeared healthy 32 days after herbicide application, while plants supplied with water throughout the experiment were completely chlorotic/necrotic and had main stem detachment from within the leaf sheaths. In the field, plants maintained unirrigated until 14 days after spraying with fluazifop-butyl (0.25 kg a.i./ha) or glyphosate (0.18 kg a.i./ha) showed greater tolerance to the herbicides than plants irrigated regularly. Values for seed head yield for water stressed and irrigated plants, 45 days after applying fluazifop-butyl, were 66 g and zero g dryweight/m² respectively. Comparable values for glyphosate treated plants were 65 g and 25 g dryweight/m². Radiolabel studies indicated that in comparision with well watered plants, water stressed plants absorbed 20% less applied ¹⁴C-glyphosate. In addition, the proportion of absorbed ¹⁴C-glyphosate translocated from the treated leaf was 15% less under water stress conditions. Uptake of ¹⁴C-fluazifop-butyl was similar under well watered and water stress conditions and was 30-40% of that applied. The proportion of absorbed ¹⁴C-activity which was transported was very low, but was greater under well watered conditions (7.6%) than under water stress conditions (4.4%). Under well watered conditions in the laboratory and field, fluazifop-butyl (0.25 kg a.i./ha) and glyphosate (0.18 kg a.i./ha) were less toxic at low nitrogen than high nitrogen. For example, 34 days after spraying with fluazifop-butyl under laboratory conditions total plant dry weight was 1.51 g and 0.56 g at 1.0 mol/m³ and 10 mol/m³ applied nitrate respectively. As with soil water content, soil nitrogen content had no effect on uptake of fluazifop-butyl. However, the proportion of absorbed fluazifop-butyl which was translocated out of the treated lamina was greater under high nitrogen conditions (26.1 %) than under low nitrogen conditions (9.3%). Under laboratory conditions, addition of 200 µg GA₃to the leaf sheaths two days prior to spraying with fluazifop-butyl or glyphosate increased the efficacy of both herbicides at low nitrogen. Similarly, under field conditions application of GA₃ (0.21 kg/ha) two days prior to spraying with glyphosate increased the performance of the herbicide against Avena sativa L. growing in a nitrogen depleted soil. At harvest, seed head yield for GA₃ treated and non-treated plants was zero and 7.4 g dry weight/m² respectively. Experiments with Avena latua L. showed that this species was tolerant of fluazifop-butyl and glyphosate when grown in low water or low nitrogen conditions. Under water stress conditions, pre-treatment with GA₃ increased the phytotoxicity of fluazifop-butyl to Avena latua L. Similarily, GA₃ enhanced the phytotoxicity of glyphosate to Avena latua L. grown under low nitrogen conditions. Reduced performance of fluazifop-butyl under stress conditions involves a reduction in translocation of herbicide to meristems, but other factors are likely to be involved. It was concluded that for glyphosate, reductions in uptake and translocation of the herbicide are important factors causing reduced performance of this herbicide under stress conditions. Possible reasons for GA₃ enhancement of fluazifop-butyl and glyphosate activity under stress conditions are discussed and the potential of growth regulators as adjuvants is considered.
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Stokes, Tania Selvayogini. "Gibberellins and cytokinins in Rumex acetosa L." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621418.
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Huntley, Rachel Paula. "Cytokinins and gibberellins in oil palm sex determination." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388546.
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Nour, J. M. "The transport of gibberellins by cultured plant cells." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332612.
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Castellaro, Simon John. "Aspects of the chemistry and biosynthesis of gibberellins." Thesis, University of Bristol, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329885.
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Steenkamp, Emma Theodora. "Molecular taxonomic studies of selected species in the Gibberella fujikuroi complex." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-06092006-114803/.
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Ertekin, Ozlem. "The Effect Of Indole Acetic Acid, Abscisic Acid, Gibberellin And Kinetin On The Expression Of Arf1 Gtp Binding Protein Of Pea (pisum Sativum L. Cv. Araka)." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608902/index.pdf.
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ADP Ribosylation Factor 1 (ARF1) is a universal small GTP binding protein
which has an important role in vesicular trafficking between endoplasmic
reticulum and Golgi. ARF1 is a basic component of Coat Protein I (COPI) vesicles
which have functions in both formation of coatomer complex and recruitment of
cargo proteins. In this study, the expression ARF1 was analyzed in pea (P. sativum
L. cv. Araka) grown at different developmental stages. Because of the differential
hormonal levels at corresponding stages, the effects of hormones on ARF1
expression were also studied.
The results of present research show that ARF1 expression in embryos and 2 days
grown plants after germination is lower when compared to 6 days grown plants. In
order to see the hormonal effect, 3 weeks old plants were supplied with 50µM of each hormone for 3 times on alternate days. Protein extraction, cell fractionation,Western blot was carried out and immunoblot analysis was conducted with AtARF1 polyclonal antibodies. It was shown that, in pea shoots, abscisic acid and gibberellin increases the inactive GDP bound ARF1 by hydrolyzing ARF-GTP through activating ARFGTPase activating protein (ARF-GAP) or partially inhibiting ARF-Guanine Nucleotide Exchange Factor (ARF-GEF). In roots, ARF-GDP (cytosolic fraction), ARF-GTP (microsomal fraction) and total amount of ARF1 (13.000 x g supernatant fraction) were down regulated by ~11, ~19 and ~11 fold respectively with the application of gibberellin
and by ~11, ~7 and ~3 fold respectively with the application of abscisic acid
when compared to control plants. These results indicate the importance of plant hormones in the regulation of ARF1 in pea.
15
Penny, Martin. "New methods for the syntheses of biologically important gibberellins." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386024.
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Boother, Gillian Margaret. "Gibberellins and genetic control of shoot growth in barley." Thesis, University of Bristol, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330035.
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Doong, Tzyy-Jye. "Regulation of Gibberellin Metabolism by Environmental Factors in Arabidopsis Thaliana." Columbus, Ohio : Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1034085989.
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Thesis (Ph. D.)--Ohio State University, 2002.Title from first page of PDF file. Document formatted into pages; contains xi, 148 p.; also contains graphics (some col.). Includes abstract and vita. Advisor: James Metzger, Dept. of Horticulture and Crop Science. Includes bibliographical references (p. 132-148).
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Holmes, Helen Frances. "The role of gibberellin in bolting in sugar beet." Thesis, University of Cambridge, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709529.
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Eriksson, Sven. "The role of gibberellins in the regulation of Arabidopsis flowering time /." Umeå : Dept. of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200693.pdf.
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Schauvinhold, Ines. "Influence of gibberellins on trichome initiation and secondary metabolism in tomato." Thesis, University of York, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479511.
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Dolan, S. C. "The synthesis, characterisation and metabolism of some selected gibberellins and kaurenoids." Thesis, University of Bristol, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370825.
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Makinson, Ian Kenneth. "The synthesis and metabolism of some novel gibberellins and related compounds." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328232.
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Camut, Lucie. "Rôle des gibbérellines dans l’adaptation des plantes à la disponibilité en azote." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAJ109.
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Les gibbérellines (GAs) sont des phytohormones régulant divers aspects de la croissance et du développement de la plante en réponse aux signaux endogènes et exogènes. Au niveau moléculaire, les GAs stimulent la dégradation des protéines DELLA, répresseurs nucléaires de croissance. L’azote (N), macronutriment essentiel au développement de la plante, représente un des facteurs les plus limitant pour la productivité agricole. Le nitrate (NO3-), principale source de N pour les plantes cultivées, est une molécule soluble dont la disponibilité varie dans l’espace et le temps. Depuis la Révolution Verte des années 1960, l’application d’engrais azotés et l’utilisation de variétés de céréales semi-naines (altérées dans leurs réponses aux GAs) à forts rendements ont permis d’augmenter significativement la productivité agricole. Récemment, il a été rapporté que des transporteurs NO3 - appartenant à la famille des NPF (NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY) étaient capables de transporter des GAs. Malgré les liens historiques et scientifiques établis entre les GAs et le NO3-, peu d’études se sont intéressées à l’effet du nitrate sur la biosynthèse, le transport et la signalisation GA chez les plantes. A l’aide d’approches génétiques, moléculaires et biochimiques réalisées chez Arabidopsis et le bl, ce travail de thèse démontre que le nitrate augmente la production et le transport acropète de GA12 (un intermédiaire de biosynthèse de GAs) et en conséquence, stimule la dégradation des répresseurs DELLAs. La diminution de l’abondance des DELLAs active la division cellulaire et donc la croissance de la plante. Par ailleurs, à l’aide de micro-greffes et de tests d’import de GAs réalisés dans des oocytes de Xenopus laevis, nous montrons que NPF2.12 et NPF2.13 facilitent le transport basipète de GA12 et du nitrate. Enfin, nous montrons que le transport acropète de GA12 est accru en réponse à une élévation de la température ambiante. Pris dans leur ensemble, ces résultats révèlent que la biosynthèse et le transport de GAs sont finement régulés en réponse à la disponibilité en nitrate et aux fluctuations de la température, permettant une croissance adaptée et optimale de la planteThe phytohormones gibberellins (GAs) regulate major aspects of plant growth and development in response to endogenous and exogenous signals. GAs promote growth by stimulating the degradation of nuclear growth repressing DELLA proteins. Nitrogen (N), a macronutrient essential for plant development, is one of the most limiting factors for agricultural productivity. Nitrate (NO3-) represents the main N source for cultivated plants but its availability fluctuates in both time and space due to its high solubility. Since the Green Revolution in the 1960’s, the use of N-fertilizers associated with high-yielding semi-dwarf cereal varieties, altered in GA responses, led to impressive yield increases. Recently, it has been reported that some NO 3 - transporters belonging to the NPF family (NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY), were able to transport GAs. Despite these observations, the effect of nitrate on GA biosynthesis, transport and signaling pathway is still unknown. Using genetics, molecular and biochemical approaches performed in Arabidopsis and wheat, this thesis work demonstrates that nitrate activates GA biosynthesis and GA12 transport (an inactive GA precursor), and as a consequence, DELLA protein degradation. The reduction in DELLA abundance increases cell division rate and thus plant growth. Moreover, through micrograftings and GA import assays in Xenopus laevis oocytes, we show that NPF2.12 and NPF2.13 facilitate the basipetal transport of GA12 and nitrate. Finally, we show that GA12 transport is enhanced by a small elevation of the ambient temperature. Altogether, these results reveal that GA biosynthesis and transport are tightly regulated in response to nitrate availability and temperature changes, enabling adaptive and optimal growth of the plant
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Buzzello, Gederson Luiz. "Uso de reguladores no controle do crescimento e no desempenho agronômico da cultura da soja cultivar CD 214 RR." Universidade Tecnológica Federal do Paraná, 2010. http://repositorio.utfpr.edu.br/jspui/handle/1/240.
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O acamamento de plantas provoca perdas significativas no rendimento de grãos da
cultura da soja e por isso estratégias de manejo para minimizar o acamamento são
importante necessidade na agricultura atual. O objetivo desse trabalho foi estudar
ação de reguladores de crescimento vegetal sobre o acamamento e outras características agronômicas da cultivar de soja CD 214 RR, em épocas de semeadura e densidades distintas. Foram conduzidos dois experimentos na Estação Experimental da Universidade Tecnológica Federal do Paraná, Campus Pato Branco. No primeiro experimento foram testados diferentes reguladores de
crescimento, sob concentrações distintas. O delineamento experimental foi inteiramente ao acaso com trinta e um tratamentos e quatro repetições. As quatro melhores combinações de reguladores/concentrações neste experimento foram utilizadas no segundo experimento. O segundo experimento foi conduzido em delineamento experimental de blocos ao acaso, com 3 repetições, em um esquema fatorial 5x3x3, em que o primeiro fator correspondeu às quatro combinações de
reguladores/concentrações selecionadas no primeiro experimento e, também, a
testemunha sem aplicação; o segundo fator correspondeu a três diferentes épocas
de semeadura (01 de novembro, 15 de novembro, e 11 de dezembro); o terceiro
fator correspondeu a três diferentes densidades de semeadura, em que a população
final para cada densidade foi de 200.000, 300.000 e 400.000 plantas ha-1. No primeiro experimento, foram avaliados o acamamento, injúria e estatura de planta, durante o desenvolvimento da cultura. No segundo experimento também foram avaliadas estas variáveis, somente ao final do ciclo da cultura. No primeiro experimento foram coletadas amostras de plantas em 0,45 m2, na área útil da parcela, para posterior determinação dos componentes do rendimento, no estádio R9. Uma amostra foi coletada no estádio R8, representada por 10 plantas por
parcela, em que foi obtido o índice de colheita e rendimento biológico aparente. Em
ambos os experimentos, no estádio R9 da cultura, houve a colheita do restante da
área útil da parcela, para determinação do rendimento de grãos. Os dados obtidos foram submetidos à análise de variância pelo teste F e foram comparados através de testes de comparação de médias. A relação entre variáveis dependentes e independentes foi ajustada através de regressão polinomial. Todos os tratamentos, de todos os seis grupos de reguladors vegetais foram eficientes em controlar o acamamento durante a maior parte do ciclo da cultura. O grupo do precursor de etileno ocasionou maior grau de fitotoxidade à cultura. Os compostos inibidores de auxina, inibidores de protox e bioestimulantes (AIB, GA3 e cinetina) apresentaram bons resultados na redução de estatura e do acamamento, apresentando grau de fitotoxidade leve e rápida recuperação dos sintomas de injúria. Os reguladores
trinexapac ethyl (312,5 g ha-1), IBA+GA3+cinetina (0,0375+0,0375+0,0675 g ha-¹) e lactofen (144 g ha-1) resultaram em rendimento de grãos mais elevados.
Isoladamente, as três concentrações de ethephon estudadas apresentam menor número de vagens por planta, menor peso de grão e menor rendimento de grãos. Os efeitos de fitorreguladores sobre o rendimento de grãos e componentes foram dependentes dos níveis em que estes foram aplicados sobre as plantas de soja. Onze tratamentos perfizeram o grupo que apresentou os rendimento de grãos mais elevados, entre eles os compostos por trinexapac ethyl (312,5 g ha-1),
IBA+GA3+cinetina (0,0375+0,0375+0,0675 g ha-1) e lactofen (144 g ha-1). Entre
todos os tratamentos, três concentrações de ethephon estudadas apresentam menor
número de vagens por planta, menor peso de grão e menor rendimento de grãos. O lactofen (144 g ha-1) promoveu maior redução em estatura, em plantas semeadas na primeira (01/11/08) e terceira época (11/12/08). Já o cloreto de mepiquat (250 g ha-1)foi mais eficaz na redução de estatura de plantas da terceira época de semeadura (11/12/08). O menor acamamento ocorreu na segunda época de semeadura, na densidade de 200.000 plantas ha-1. Considerando-se a média de densidades e
épocas de semeadura, os reguladores TIBA (6 g ha-¹), lactofen (144 g ha-¹) e
AIB+GA3+Cinetina (0,0375+0,0375+0,0675 g ha-¹) apresentaram o melhor desempenho na redução do acamamento. O maior rendimento de grãos de soja ocorreu na semeadura de 11 de dezembro, não sendo influenciado pela densidade de plantas nesta época. O menor rendimento de grãos em soja ocorreu na
semeadura do início de novembro, na densidade de 400.000 plantas ha-1. No
segundo experimento, as plantas de todos os tratamentos com regulador de crescimento não apresentaram sintoma de injúria na avaliação realizada no estádio R1 da cultura.The lodging of plants causes significant losses in grain yield of soybean and therefore management strategies to minimize the lodging are important in agriculture today. The aim of this work was to study the action of reducers of plant growth on lodging and other agronomic characteristics of soybean CD 214 RR at sowing dates and different densities. Two experiments were conducted at the Experimental Station of the Federal Technological University of Paraná, Pato Branco Campus. In the first experiment, testing different reducers of growth under different concentrations. The experimental design was completely andomized thirty-one treatments and four replicates. The four best combinations of concentrations in this experiment were used in the second experiment. The second experiment was conducted in a randomized block design with 3 replicates in a 5x3x3 factorial design, where the first factor corresponding to four combinations of concentrations selected in the first experiment (and also the control), the second factor corresponded to three different sowing dates (01 November, 15 November, and December 11), the third factor corresponded to three different plant densities in the final population for each density was 200.000, 300.000 and 400.000 plants ha-1. The first experiment examined the lodging, injury and plant height during the development of the culture. In the second experiment also evaluated these variables at the end of the cycle. In the first experiment samples were collected from plants in 0,45 m2 in each parcel, for later determination of yield components, the stage R9. A sample was collected at the R8 stage, represented by 10 plants per plot, which was obtained harvest index and biological yield apparent. In both experiments, the R9 stage of culture, there was the harvest of the remainder of each parcel to determine the yield. The data were subjected to analysis of variance by F test and were compared by means of comparison tests of means. The relationship between dependent and independent variables was adjusted by polynomial regression. All treatments in all six groups retardant were efficient in controlling the lodging for most of the crop cycle. The precursor of ethylene group caused a greater degree of phytotoxicity to the crop. The compounds of auxin inhibitors, protox and biostimulators (IBA, GA3 and kinetin) were able to reduce height and lodging, with slight degree of phytotoxicity and with rapid recovery of symptoms injury. Reducers trinexapac ethyl (312.5 g ha-1), IBA +GA3 +kinetin (0.0375, 0.0375 and 0.0675 g ha-¹) and lactofen (144 g ha-1) resulted in yield higher. Individually, the three concentrations of ethephon studied have a lower number of pods per plant, lower weight and lower grain yield. The effects of growth regulators on yield and components were dependent on the levels at which they are applied on the soybean plants. Eleven treatments accounted for the group the higher yield, among them the trinexapac ethyl (312.5 g ha-1), IBA GA3 kinetin (0.0375, 0.0375 and 0.0675 g ha-¹) and lactofen (144 g ha-1). Among all the treatments, the plants that received the three concentrations of ethephon studied have a lower number of pods per plant, lower weight and lower grain yield. The lactofen (144 g ha- 1) provided greater reduction in height, plants sown in the first (01/11/08) and third time (11/12/08). Since the chloride doses (250 g ha-1) was more effective in reducing plant height of the third sowing date (11/12/08). Smallest lodging occurred in the second sowing date, density of 200.000 plants ha-1. Considering the average densities and sowing dates, regulators TIBA (6 g ha-1), lactofen (144 g ha-1) and IBA +GA3+Kinetin (0.0375+0.0375+0.0675 g ha-1) showed the best performance in reducing lodging. The highest yield of soybean at sowing occurred on December 11 and is not influenced by the density of plants at this time. The lower yield in soybean planting occurred in early November, with a density of 400.000 plants ha-1. In the second experiment, plants of all treatments with growth retardant had no symptoms of injury in the assessment at the R1 stage of culture.
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Sarkar, Sunita. "Relationship between gibberellins, height and stress tolerance in barley (Hordeum vulgare L.) seedlings." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ56695.pdf.
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Felipo, Benavent Amelia. "Modulation of primary meristem activity by gibberellins through DELLA-TCP interaction in Arabidopsis." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/82237.
Full textAbstract:
Plant development is an iterative process of organ formation from the primary meristems of the plant. Meristem activity is driven by dynamic transcriptional programs that determine cell fate and identity as cells are displaced trough the meristematic tissue to initiate organ primordia. This regulatory network includes members of the TCP and KNOX family of transcription factors, and integrates external and intrinsic cues to efficiently adapt meristem activity to an ever-changing environment. However, how this integration occurs is not clear yet.
DELLA proteins have been proposed to modulate transcriptional circuits in plants in response to environmental signals. Although they do not show DNA binding capacity, DELLAs regulate transcription through physical interaction with a large number of DNA-binding transcription factors and other transcriptional regulators. Given the observed interaction between DELLAs and several members of the TCP family of transcription factors, we have explored the relevance of this interaction in the regulation of primary meristems. We have confirmed that DELLAs interact with members of both Class I and Class II TCPs, and prevent their ability to regulate downstream targets. In the embryonic roots, DELLAs maintain a dormant meristem by impairing TCP14/15-dependent activation of cell-cycle genes. On the other hand, DELLAs participate in the establishment of the shoot apical meristem domain that keeps an indeterminate fate, through the control of KNAT1 gene expression by the TCP2/4-AS1 regulatory module. In summary, this Thesis provides a mechanistic framework to eventually explain environmental regulation of meristem activity.El desarrollo de las plantas es un proceso iterativo de formación de órganos a partir de los meristemos primarios de la planta. La actividad meristemática está dirigida por programas transcripcionales dinámicos que determinan el destino y la identidad celular conforme las células son desplazadas a través del tejido meristemático para iniciar el primordio del órgano. Esta red regulatoria incluye miembros de las familias de factores de transcripción TCP y KNOX, e integra señales externas e intrínsecas para adaptar eficientemente la actividad meristemática al medio ambiente, siempre cambiante. Sin embargo, la manera en que esta integración ocurre no se ha desvelado todavía. Se ha propuesto que en plantas, las proteínas DELLA modulan los circuitos transcripcionales en respuesta a señales medioambientales. Aunque no muestran capacidad de unión al ADN, las DELLAs regulan la transcripción a través de su interacción física con un gran número de factores de transcripción capaces de unirse al ADN y otros reguladores transcripcionales. Dada la interacción observada entre las DELLA y varios miembros de la familia de factores de transcripción TCP, hemos explorado la relevancia de esta interacción en la regulación de los meristemos primarios. Hemos confirmado que las DELLA interaccionan con miembros de las dos clases de TCPs (Clase I y Clase II) e impiden su capacidad de regular dianas aguas abajo. En la raíz del embrión, las DELLAs mantienen el meristemo durmiente al impedir la activación de los genes de ciclo celular dependiente del módulo TCP14/15. Por otro lado, las DELLAs participan en el establecimiento del meristemo apical del tallo, que mantiene un estado indiferenciado, a través del control el módulo TCP2/4-AS1, el cual regula la expresión del gen KNAT1. En resumen, esta Tesis aporta un marco mecanístico para explicar, con el tiempo, la regulación medioambiental de la actividad meristemática.
El desenvolupament de les plantes consiteix en un procés iteratiu de formació d'órgans a partir dels meristems primaris. L'activitat meristemàtica està diridida per programes transcripcionals dinàmics que determinen el destí i la identitat cel.lular a mesura que les cèl.lules es van allunyant del meristem per formar els primordis d`órgans. Esta xarxa de regulació inclou membres de les famílies de factors de transcripció TCP i KNOX, i integra senyals externes i intrínseques per adaptar d'una manera eficient l'activitat del meristem als canvis del medi ambient. No obstant, no es coneix de quina manera la planta fa esta integració. S'ha proposat que les proteïnes DELLA modulen estes xarxes transcripcionals en resposta a senyals del medi. Estes proteïnes no tenen capacitat d'unir-se a l'ADN, però regulen la transcripció mitjançant la interacció amb factors de transcripció i altres reguladors transcripcionals. Donada la interacció entre les proteïnes DELLA i alguns membres de la família de factors de transcripció TCP, hem explorat la rellevància d'esta interacció a la regulació dels meristems primaris. Hem confirmat que les DELLA interaccionen amb membres de les dos classes de TCPs (Classe I i Classe II) i els impedeixen regular les seues dianes. A l'arrel de l'embrió, les DELLA mantenen el meristem dorment al impedir l'activació de gens del cicle cel.lular depenent del mòdul TCP14/15. Per una altra banda, les DELLA particípen a l'establiment del meristem apical de la tija, al que mantenen en un estat indiferenciat, mitjançant el control del mòdul TCP2/4-AS1, que regula l'expressió de KNAT1. En resum, esta Tesi aporta un marc mecanístic per poder explicar, més endavant, la regulació mediambiental de l'activitat meristemàtica.
Felipo Benavent, A. (2017). Modulation of primary meristem activity by gibberellins through DELLA-TCP interaction in Arabidopsis [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/82237
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Yan, Jia. "Effects of Gibberellin 2-oxidase, Phytochrome B1, and Bas1 gene transformation on creeping bentgrass photomorphogenesis under various light conditions." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1168027982.
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Björklund, Simon. "Plant hormones in wood formation : novel insights into the roles of ethylene and gibberellins /." Umeå : Dept. of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200781.pdf.
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Silva, Rudieli Machado da. "Componentes da produção e produtividade da mandioca de mesa em função do arranjo de plantio e modos de aplicação de regulador de crescimento /." Botucatu, 2019. http://hdl.handle.net/11449/181549.
Full textAbstract:
Orientador: Adalton Mazetti FernandesBanca: Marcelo de Almeida Silva
Banca: Samuel Ferrari
Resumo: A importância econômica da mandioca (Manihot esculenta Crantz) está relacionada ao uso de suas raízes tuberosas na alimentação humana, animal e na produção de fécula e farinha, no entanto sua produção é limitada pela baixa produtividade média brasileira. Sistemas adensados de plantio são utilizados no aumento da produtividade da mandioca, porém com a obtenção de raízes menores e mais finas, devido à maior competição entre as plantas. Assim, a utilização de reguladores de crescimento pode ser uma tecnologia eficiente para superar essa limitação em sistemas de plantio adensado. O objetivo deste estudo foi avaliar o crescimento, produtividade e qualidade das raízes tuberosas de mandioca de mesa cultivar IAC 576-70 em função do arranjo de plantio e modos de aplicação do regulador de crescimento vegetal paclobutrazol. O delineamento experimental utilizado foi o de blocos ao acaso, no esquema de parcela subdividida, e o experimento conduzido na Fazenda Experimental São Manuel, pertencente à Faculdade de Ciências Agronômicas/UNESP, no ano agrícola 2017/18. As parcelas foram representadas por cinco arranjos de plantio (1: 1,00 x 1,00 (tradicional); 2: 1,00 x 0,50; 3: 0,85 x 0,59; 4: 0,70 x 0,71 e 5: 0,55 x 0,91 m), enquanto as subparcelas foram representadas por formas de aplicação do regulador de crescimento paclobutrazol (1: Controle sem aplicação de regulador, 2: Aplicação aos 3 meses após a emergência - MAE, 3: Aplicação aos 3 e 5 MAE e 4: Aplicação aos 3, 5 e 7 MAE), o qual foi ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The economic importance of cassava (Manihot esculenta Crantz) is related to the use of its tuberous roots in human food, animal feed and in the production of starch and flour, however its production is limited by the the low Brazilian productivity. Denser planting systems are used to increase cassava productivity, but with the production of smaller and thinner roots due to increased competition between plants. Thus, the use of plant growth regulators may be an efficient technology to overcome this limitation in densely planted systems. The objective of this study was to evaluate the growth, productivity and quality of tuberous roots of sweet cassava cv. IAC 576-70 in function of different planting arrangements and application methods of plant growth regulator paclobutrazol. The experimental design was a randomized block design, in a split-plot scheme, and the experiment was conducted at the São Manuel Experimental Farm of the College of Agricultural Science/UNESP during the 2017/18 crop year. The plots were represented by five planting arrangements (1: 1.00 x 1.00 (traditional), 2: 1.00 x 0.50, 3: 0.85 x 0.59, 4: 0.70 x 0.71 and 5: 0.55 x 0.91 m), while the subplots were represented by application forms of the growth regulator paclobutrazol (1: Control without regulator application, 2: Application at 3 months after emergence - MAE, 3: Application at 3 and 5 MAE and 4: Application at 3, 5 and 7 MAE), which was applied via foliar at the dose of 100 g ha-1 a.i. (active ingredient) at each application time. The results indicated that the growth regulator has no effect on the height and number of leaves of sweet cassava plants at the dose used. The use of growth regulator increased fiber and protein contents, and decreased the cooking time of the roots, which are nutritionally interesting. The dry matter accumulation of the aerial plant part, root stem, tuberous roots, and total and commercial root yields ...
Mestre
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Duvalsaint, Marvin Duvalsaint. "The Effects of Phytohormones and Isoprenoids in Dihydroartemisinin-induced Dormancy in the Erythrocytic Stages of Plasmodium falciparum." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6495.
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Our ability to control malaria has been challenged by increasing antimalarial resistance. Plasmodium falciparum undergoes dormancy in the blood stages which is hypothesized to be a means by which they are able to survive under drug pressure. This helps select for resistant parasites which grow following removal of drug. The mechanisms behind dormancy and the subsequent recrudescence are not fully understood but translating knowledge from related organisms which undergo a similar phenomenon might shed some light. Higher plants utilize dormancy during the early development stages to survive under unfavorable conditions, increasing fitness of the seedling and ensuring viability when this is released and it develops into a mature plant. Abscisic acid (ABA) and gibberellic acid (GA) antagonistically regulate this in response to environmental cues. We have found that both can be supplemented to dihydroartemesinin-induced dormant parasites to stimulate early recovery. Fluridone, an ABA inhibitor that releases dormancy in plants, was found to prolong it and cause a delay in recrudescence. These effects were observed in artemisinin sensitive and resistant strains.
The apicoplast is required for recovery and supplementation of essential isoprenoid, isopentyl pyrophosphate (IPP), in apicoplast deficient parasites is sufficient enough to compensate for the lack of the organelle in antibiotic treated parasites. IPP plays an important role in development and metabolism of blood stage parasites as a key component of numerous secondary metabolites and protein activity by prenylation of isoprenoids. Its role in dormancy has not been explored prior to this study.
Carotenoids are long-chained ABA precursors consisting of two molecules of geranylgeranyl pyrophosphate (GGPP). Several carotenoids as well as enzymes in that pathway have been identified in the blood stages of P. falciparum. The Apicomplexan parasite, Toxoplasma gondii synthesizes ABA, where it plays a role in signaling and development. To date ABA has not been detected in P. falciparum due to limitations in methods previously utilized. We have found that parasites with fosmidomycin inhibition of isoprenoids can be rescued with GGPP supplementation which we planned to use to further elucidate the carotenoid biosynthetic pathway.
We hypothesized that Plasmodium has retained the ability to biosynthesize ABA and aimed to confirm this. We developed a novel method to label GGPP with 13C on three of its isoprene units. This would be used to metabolically label isoprenoid inhibited P. falciparum for incorporation through the carotenoid pathway for detection of 13C-ABA.
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Dry, P. R. "Primary bud-axis necrosis of grapevines /." Title page, contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09A/09ad798.pdf.
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Abbas, Mohamad. "The control of auxin homeostasis through the regulation of IAMT1 by DELLA proteins." Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/39348.
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The plant hormones gibberellins (GAs) and auxin display overlapping activities in the regulation of multiple developmental processes, including the differential growth that mediates the response to tropic stimuli and the formation of the apical hook. Several mechanisms have been proposed that explain the interaction between these two hormones, such as the regulation of auxin transport by GAs, and the regulation of GA biosynthesis by auxin. GAs are known to exert their action at the transcriptional level by promoting the degradation of DELLA proteins, which in turn interact with numerous transcription factors and modulate their activity. We have identified INDOLE-3-ACETIC ACID METHYLTRANSFERASE 1 (IAMT1) as one of the earliest target genes upregulated after conditional expression of the DELLA protein GAI in Arabidopsis thaliana. In this Thesis, we have addressed two main issues: (1) the contribution of IAMT1 to auxin homeostasis and its biological relevance; and (2) the molecular mechanism by which DELLAs are able to induce the expression of IAMT1.
Using combinations of iamt1 loss-of-function mutants and reporter lines for auxin accumulation and activity, we have found that IAMT1 activity is essential for proper generation and maintenance of the auxin gradients that underlie differential growth. According to our results, the role of IAMT1 would be to restrict polar auxin transport especially during the response to tropic stimuli, preventing excessive auxin accumulation in the responding tissues, and IAMT1 exerts this function, at least in part, by inhibiting the expression of the PIN genes, encoding auxin efflux carriers.
Regarding the regulation of IAMT1 expression by DELLAs, dissection of the promoter, in silico analysis of putative DELLA partners, and molecular genetic analysis of reporter lines has allowed us to identify two mechanisms with different relevance depending on the environmental conditions, and through different cis elements. In etiolated seedlings, DELLA proteins are recruited by DORNRÖSCHEN (DRN) to the IAMT1 promoter to induce IAMT1 expression. In the light and in a temperature-dependent manner, DELLA proteins inhibit the DNA-binding activity of PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and BRI1 EMS-SUPPRESSOR1(BES1), which act as repressors of IAMT1 expression.
The work presented here highlights how GAs may affect local accumulation of auxin, being particularly relevant in processes that involve differential growth.Abbas, M. (2014). The control of auxin homeostasis through the regulation of IAMT1 by DELLA proteins [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/39348
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Johnson, Kerry. "Photoperiod induction, Gibberellic acid, mulch and row cover effects on fresh cut flower production of three Rudbeckia hirta L. cultivars." Diss., Mississippi State : Mississippi State University, 2006. http://sun.library.msstate.edu/ETD-db/ETD-browse/browse.
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Wood, Nicholas D. "Studies towards the synthesis of mycinolide III, mycinoic acids I & II and 1β,2α-dimethyl gibberellins." Thesis, University of Bristol, 1996. http://hdl.handle.net/1983/1322f2e7-4563-4a44-991b-a4bf89a5c81b.
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Amaro, Amanda Cristina Esteves [UNESP]. "Respostas fisiológicas à aplicação de reguladores vegetais e nutrientes em videira ‘crimson seedless'." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/108724.
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000766009.pdf: 2133283 bytes, checksum: ba937fe476457437b0b6e44206820ee8 (MD5)O presente trabalho objetivou avaliar o efeito da aplicação foliar da mistura de auxina (Ax), citocinina (CK) e giberelina (GA), isolada ou combinada com a mistura de nutrientes, cobalto (Co) e molibdênio (Mo), em videira ‘Crimson Seedless’, buscando analisar seus efeitos na duração da atividade fotossintética das folhas e no metabolismo e desenvolvimento da planta, bem como no aumento da produção e qualidade de frutos. Os experimentos foram desenvolvidos no município de Juazeiro – BA, Brasil, em blocos casualizados, com quatro tratamentos e seis blocos. Os tratamentos foram: T1 - Testemunha; T2 - CK+Ax+GA 1,8L ha-1; T3 - CK+Ax+GA 1,8L ha-1 + Co+Mo 1,0L ha-1; e T4 - CK+Ax+GA 1,8L ha-1 + Co+Mo 1,5L ha-1. As aplicações foram realizadas em três fases: primórdio de inflorescência, bagas chumbinho, e alongamento de bagas. No primeiro experimento, avaliou-se a duração da atividade fotossintética das folhas, através de avaliações nas trocas gasosas em folhas marcadas logo após a brotação, até o final do ciclo. No segundo experimento, foram avaliadas as trocas gasosas, atividades de enzimas antioxidantes, teores de carboidratos e clorofilas aos 3, 5, 7, 14 e 21 dias após a 1ª aplicação; aos 1, 3 e 5 dias após a 2ª aplicação e aos 1, 3, 5, 7, 14, 21 e 28 dias após a 3ª aplicação (DAA). Assim, as plantas mantiveram a atividade fotossintética durante todo o ciclo, até o final das avaliações, aos 133 dias após a brotação das folhas. Entretanto, observou-se que a aplicação de reguladores vegetais e nutrientes antecipou o momento em que as folhas atingiram a taxa de assimilação de CO2 máxima, indicando que esses tratamentos otimizaram o processo fotossintético. Ao mesmo tempo, as taxas de assimilação de CO2 e eficiência de carboxilação começaram a apresentar maior eficiência após 14 DAA, assim como maiores teores de clorofilas, carotenoides e ...
The present study aimed to evaluate the effect of foliar application of auxin (Ax), cytokinin (CK) and gibberellin (GA) mixture, isolated or combined with the cobalt (Co) and molybdenum (Mo) mixture, in 'Crimson Seedless' grapevine, analyzing their effects on photosynthetic activity duration, metabolism and development of the plant, as well as increase production and fruit quality. The experiments were conducted in Juazeiro - BA, Brazil, in a randomized block design with four treatments, six blocks, with four plants each. Treatments were: T1 - Control; T2 - CK+Ax+GA 1.8L ha-1, T3 - CK+Ax+GA 1.8L ha-1 + Co+Mo 1.0L ha-1, and T4 - CK+Ax+GA 1.8L h-1 + Co+Mo 1.5L h-1. The treatments applications were carried out in three phases: inflorescence primordial stage, when berries were with 6 to 8 mm in diameter and berries elongation. In the first experiment, the photosynthetic activity duration was assessed by evaluating gas exchanges in leaves that were marked soon after sprouting, until the end of the cycle. In the second experiment, were evaluated gas exchanges, antioxidant enzymes activities, levels of carbohydrates and chlorophyll at 3, 5, 7, 14 and 21 days after the 1st application, at 1, 3 and 5 days after 2nd application and at 1, 3 , 5, 7 , 14, 21 and 28 days after the 3rd application (DAA). Thus, plants maintained their photosynthetic activity during the whole cycle, until the end of evaluations, for 133 days after sprouting leaves. However, it was observed that the application of plant growth regulators and nutrients anticipating the moment when the leaves reached the maximum absorption rate of CO2, indicating that these treatments have optimized the photosynthetic process. At the same time, rates of CO2 assimilation and carboxylation efficiency began to show greater efficiency after 14 DAA, as well as higher levels of chlorophylls, carotenoids and sugar concentrations, as in the 1st far as ...
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Amaro, Amanda Cristina Esteves 1985. "Respostas fisiológicas à aplicação de reguladores vegetais e nutrientes em videira 'crimson seedless' /." Botucatu : [s.n.], 2014. http://hdl.handle.net/11449/108724.
Full textAbstract:
Orientador: João Domingos RodriguesBanca: Elizabeth Orika Ono
Banca: Gisela Ferreira
Banca: Osvaldo Ferrarese Filho
Banca: Stella Consorte Cato
Resumo: O presente trabalho objetivou avaliar o efeito da aplicação foliar da mistura de auxina (Ax), citocinina (CK) e giberelina (GA), isolada ou combinada com a mistura de nutrientes, cobalto (Co) e molibdênio (Mo), em videira 'Crimson Seedless', buscando analisar seus efeitos na duração da atividade fotossintética das folhas e no metabolismo e desenvolvimento da planta, bem como no aumento da produção e qualidade de frutos. Os experimentos foram desenvolvidos no município de Juazeiro - BA, Brasil, em blocos casualizados, com quatro tratamentos e seis blocos. Os tratamentos foram: T1 - Testemunha; T2 - CK+Ax+GA 1,8L ha-1; T3 - CK+Ax+GA 1,8L ha-1 + Co+Mo 1,0L ha-1; e T4 - CK+Ax+GA 1,8L ha-1 + Co+Mo 1,5L ha-1. As aplicações foram realizadas em três fases: primórdio de inflorescência, bagas chumbinho, e alongamento de bagas. No primeiro experimento, avaliou-se a duração da atividade fotossintética das folhas, através de avaliações nas trocas gasosas em folhas marcadas logo após a brotação, até o final do ciclo. No segundo experimento, foram avaliadas as trocas gasosas, atividades de enzimas antioxidantes, teores de carboidratos e clorofilas aos 3, 5, 7, 14 e 21 dias após a 1ª aplicação; aos 1, 3 e 5 dias após a 2ª aplicação e aos 1, 3, 5, 7, 14, 21 e 28 dias após a 3ª aplicação (DAA). Assim, as plantas mantiveram a atividade fotossintética durante todo o ciclo, até o final das avaliações, aos 133 dias após a brotação das folhas. Entretanto, observou-se que a aplicação de reguladores vegetais e nutrientes antecipou o momento em que as folhas atingiram a taxa de assimilação de CO2 máxima, indicando que esses tratamentos otimizaram o processo fotossintético. Ao mesmo tempo, as taxas de assimilação de CO2 e eficiência de carboxilação começaram a apresentar maior eficiência após 14 DAA, assim como maiores teores de clorofilas, carotenoides e ...
Abstract: The present study aimed to evaluate the effect of foliar application of auxin (Ax), cytokinin (CK) and gibberellin (GA) mixture, isolated or combined with the cobalt (Co) and molybdenum (Mo) mixture, in 'Crimson Seedless' grapevine, analyzing their effects on photosynthetic activity duration, metabolism and development of the plant, as well as increase production and fruit quality. The experiments were conducted in Juazeiro - BA, Brazil, in a randomized block design with four treatments, six blocks, with four plants each. Treatments were: T1 - Control; T2 - CK+Ax+GA 1.8L ha-1, T3 - CK+Ax+GA 1.8L ha-1 + Co+Mo 1.0L ha-1, and T4 - CK+Ax+GA 1.8L h-1 + Co+Mo 1.5L h-1. The treatments applications were carried out in three phases: inflorescence primordial stage, when berries were with 6 to 8 mm in diameter and berries elongation. In the first experiment, the photosynthetic activity duration was assessed by evaluating gas exchanges in leaves that were marked soon after sprouting, until the end of the cycle. In the second experiment, were evaluated gas exchanges, antioxidant enzymes activities, levels of carbohydrates and chlorophyll at 3, 5, 7, 14 and 21 days after the 1st application, at 1, 3 and 5 days after 2nd application and at 1, 3 , 5, 7 , 14, 21 and 28 days after the 3rd application (DAA). Thus, plants maintained their photosynthetic activity during the whole cycle, until the end of evaluations, for 133 days after sprouting leaves. However, it was observed that the application of plant growth regulators and nutrients anticipating the moment when the leaves reached the maximum absorption rate of CO2, indicating that these treatments have optimized the photosynthetic process. At the same time, rates of CO2 assimilation and carboxylation efficiency began to show greater efficiency after 14 DAA, as well as higher levels of chlorophylls, carotenoids and sugar concentrations, as in the 1st far as ...
Doutor
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Barker, Whitnee Leigh. "Lateral Movement of Herbicides on Golf Course Fairways and Effects on Bentgrass Greens." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9929.
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Concern has been raised that herbicides recently registered for use in warm-season turf to control perennial ryegrass could be dislodged from treated areas and deposited on neighboring cool-season grasses. In a field study, rimsulfuron was applied at 17.5 or 35 g ai/ha to perennial ryegrass in the afternoon; the following morning while dew was still present, a greens mower was driven through the perennial ryegrass and across adjacent creeping bentgrass. Irrigation had no effect on perennial ryegrass control but reduced visible track length and injury of neighboring creeping bentgrass. When treated perennial ryegrass was not irrigated prior to simulated mowing, tire tracks were evident on adjacent creeping bentgrass for up to 30 days. Gibberellic acid at 0.12 kg ai/ha and foliar iron at 1.3 kg ai/ha, applied to creeping bentgrass when tracks first appeared, did not enhance recovery of injured creeping bentgrass. Persistence and stability of [2-pyridine 14C] rimsulfuron on turf foliage was also assessed. Rimsulfuron was absorbed by annual bluegrass and perennial ryegrass equivalently and persisted equally on turf foliage. Water extractable rimsulfuron decreased from 60% at 10 minutes after treatment to 40% at 96 hours after treatment. A substantial amount of stable rimsulfuron persists on turf foliage for up to four days. Results from both studies suggest that when applying rimsulfuron near susceptible bentgrass the lowest effective rate should be used, and irrigation should follow two hours after treatment to prevent nontarget injury.Master of Science
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Eriksson, Maria Elenor. "The role of phytochrome A and gibberellins in growth under long and short day conditions : studies in hybrid aspen /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5898-6.pdf.
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Virtanen, E. (Elina). "Effects of haulm killing and gibberellic acid on seed potato (Solanum tuberosum L.) and techniques for micro- and minituber production in northern latitudes." Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526204178.
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Abstract Seed potato is the starting point in the potato (Solanum tuberosum L.) production chain. In order to secure potato production in a variety of production conditions, plant diseases must be controlled and the yield characteristics of the used cultivars ensured. In addition, production must be cost-effective. Characteristics particular to northern production conditions include long periods of daylight and a short growing season as well as a several months long seed potato storage period. The focus of the present study is on northern production conditions and methods, including haulm killing and sprout control, which are presumed to affect seed potato quality, as well as the initial stages of the seed potato production chain, i.e. micro- and minituber production, which could influence cost-effectiveness and propagation. Haulm killing is one of the methods used in seed potato production to regulate tuber size. It is often carried out on unsenesced plants. The present results, however, indicate that cultivar properties have a greater effect on the sprouting and crop yield of seed potatoes than production-phase haulm killing or temperature sum accumulation. Nevertheless, haulm killing carried out three weeks after flowering (75 DAP) accelerated emergence. When the effect of haulm killing methods on seed potatoes was compared with natural haulm senescence, haulm killing was shown to increase disease pressure. Black scurf (Rhizoctonia Solani) was present in seed tubers whose haulm had been destroyed by mechanical or mechanical-chemical haulm killing. Naturally senesced haulm had less black scurf, and crop quantity and starch content developed to a level typical of the cultivar. Storage periods lasting several months make controlling seed potato sprouting more challenging. Therefore, use of the plant hormone gibberellic acid (GA) in sprout control was investigated. GA treatments at lower concentration (100 mM) increased the number of tubers in the cultivar Fambo. Thus, the timing of haulm killing and in the case of Fambo, GA treatment influenced the characteristics of seed potatoes. Conventionally, the first tuber generation is produced using microplants to produce minitubers in greenhouses. This production method is, however, labour-intensive, and energy and investment costs are high. With the aim of increasing production efficiency in northern production conditions, the production of minitubers in the laboratory using a novel bioreactor technology and in growth rooms using the hydroponic technique was investigated. The Liquid LabTM Rocker bioreactor system was used in vitro, all the cultivars examined (Asterix, Timo, Van Gogh and Velox) produced microtubers. The quantity of tubers produced per dish varied between 30 (for the cultivar Asterix in eight weeks) and 75 (for the cultivar Velox in 11 weeks). The results showed hydroponic production of minitubers to be successful in indoor conditions: the cultivars Desiree and Van Gogh developed their first tuber three weeks faster than Asterix, and the minituber yield was 4.5 per plant for Desiree, 7.5 for Van Gogh and 4.0 for Asterix. When the results indicate that both the Liquid LabTM Rocker production method and the hydroponic production method are suitable for mass production of seed potatoesTiivistelmä Siemenperuna on lähtökohta perunan (Solanum tuberosum L.) tuotantoketjussa. Jotta perunantuotanto turvataan eri tuotanto-olosuhteissa, on hallittava siemenperunan kasvitaudit, taattava sadontuotto-ominaisuudet ja tuotannon on oltava lisäksi kustannustehokasta. Pohjoisissa tuotanto-olosuhteissa erityispiirteinä ovat valoisuudeltaan pitkät päivät ja kestoltaan lyhyet kasvukaudet. Lisäksi siemenperunoiden varastointijakso kestää useita kuukausia. Tässä tutkimuksessa selvitettiin vaikuttavatko pohjoiset tuotanto-olosuhteet tai tuotannossa käytetyt varsistonhävitys tai itämisen hallinta siemenperunoiden laatuominaisuuksiin. Lisäksi selvitettiin siemenperunoiden ensimmäisen mukulasukupolven (mikro- ja minimukula) tuotantoa eri tekniikoilla. Siemenperunatuotannossa varsistonhävitystä käytetään mukulakoon säätelykeinona. Varsistonhävitys tehdään usein tuleentumattomaan kasvustoon. Saatujen tulosten perusteella lajikeominaisuudet vaikuttivat itämiseen ja sadontuotto-ominaisuuksiin enemmän kuin varsistonhävitys tai mukuloihin kerääntynyt lämpösumma. Varsistonhävitys kolme viikkoa kukinnasta (75 päivää istutuksen jälkeen) nopeutti kuitenkin siemenperunoiden taimettumista. Vertailtaessa varsistonhävitysmenetelmien vaikutusta siemenperunaan verranteena kasvuston luontainen tuleentuminen, varsistonhävitys lisäsi kasvitautipainetta. Mekaanis-kemiallisesti ja mekaanisesti varsistonhävityissä satomukuloissa tuli esiin seittirupea (Rhizoctonia solani). Luontaisesti tuleentuneen kasvuston sadoissa oli seittirupea vähemmän ja myös sadon määrä ja tärkkelyspitoisuus kehittyivät lajikkeelle luontaiselle tasolle. Useiden kuukausien varastointijakso vaikeuttaa siemenperunoiden itämisen hallintaa. Kun tutkittiin gibberelliinihapon (GA) käyttöä itämisen hallintaan, alhaisemman konsentraation (100mM) GA –käsittely lisäsi Fambo –lajikkeen mukulalukumäärää. Tulosten perusteella varsistonhävityksen ajoittamisella ja GA –käsittelyllä (Fambo –lajike) vaikutettiin siemenperunoiden ominaisuuksiin. Siemenperunan ensimmäisen mukulasukupolven eli minimukuloiden tuottaminen tapahtuu perinteisesti kasvihuonekasvatuksena mikrokasveista. Tuotantotapa on työvoima-, energia- ja invetointikustannuksia vaativaa. Tuotannon tehostamiseksi pohjoisissa tuotanto-olosuhteissa tutkittiin mikro- ja minimukuloiden tuotantoa eri teknologioilla. Mikromukuloita tuotettiin bioreaktorimenetelmällä laboratoriossa ja minimukuloita hydroponisella menetelmällä kasvatushuoneissa. Tulokset osoittavat, että kaikki tutkitut lajikkeet (Asterix, Timo, Van Gogh ja Velox) tuottivat bioreaktorissa mikromukuloita. Mikromukuloiden määrä vaihteli 30:sta (Asterix, 8 viikon kasvatus) 75:een (Velox, 11 viikon kasvatus). Myös minimukuloiden hydroponinen tuotanto sisätiloissa on mahdollista; kaikki lajikkeet muodostivat mukuloita, Desiree ja Van Gogh 3 viikkoa nopeammin kuin Asterix. Desiree tuotti minimukuloita 4.5 kpl/kasvi, Van Gogh 7.5 ja Asterix 4.0. Tulokset osoittavat, että molemmat menetelmät (bioreaktori ja hydroponinen) soveltuvat mikro- ja minimukuloiden massatuotantoon
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Dias, João Paulo Tadeu [UNESP]. "Etil-trinexapac em diferentes concentrações e épocas de aplicações no crescimento de figueira (Ficus carica L)." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/103297.
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000757670.pdf: 1772920 bytes, checksum: ac3e161b26a22adc394755fc3cc1f63c (MD5)Neste trabalho foram realizados três experimentos com o objetivo de estudar o efeito do regulador vegetal, etil-trinexapac, no crescimento e produção da planta de figueira (Ficus carica L.). O experimento 1 foi desenvolvido no período de 27 de agosto de 2011 a três de março de 2012 e o experimento 2, de 27 de agosto de 2012 a três de março de 2013. Os dois experimentos foram implantados em pomar comercial de cultivo de figueira cv. Roxo-de-Valinhos com quatro anos de idade, conduzidos em sequeiro (sem irrigação), sendo adicionados, regularmente, bagaço de cana nas linhas das plantas como cobertura morta (mulching) e destinando a produção de frutos verdes à indústria, no município de Caldas-MG. O experimento 3 (28 de março a 28 de julho de 2012) foi instalado em mudas de figueira cultivadas a pleno sol no Departamento de Horticultura, da Faculdade de Ciências Agronômicas do Campus de Botucatu da Universidade Estadual Paulista – UNESP, Botucatu-SP. Os três experimentos foram instalados em delineamento de blocos casualizados, considerando uma testemunha (sem aplicação) e, uma e duas aplicações de etil-trinexapac, em sete concentrações, na forma de solução: 0; 62,5; 62,5 + 62,5; 125; 125 + 125; 250; 250 + 250 e 500 mg L-1 de ingrediente ativo, distribuídos em quatro blocos. A parcela foi constituída por quatro plantas e uma planta de bordadura de cada lado da parcela. No experimento 1 e 2, a primeira pulverização foi realizada em ramos novos (brotações) padronizados com 50,0 cm de comprimento e contendo 12 entrenós (em torno de 12 gemas axilares). A segunda pulverização foi realizada nos mesmos ramos, 45 dias após a primeira aplicação. Já no experimento 3, a primeira pulverização foi realizada em ramos novos (brotações) padronizados com 26,0 cm de comprimento e contendo 16 entrenós (em torno de 16 gemas axilares). Já a segunda pulverização foi realizada nos mesmo...
In this work three experiments was to study the effect of the plant growth regulator, trinexapac-ethyl, on growth and yield of fig plant (Ficus carica L.). The experiment 1 was conducted during August 27th, 2011 to March 3th, 2012 and experiment 2, August 27th, 2012 to March 3th, 2013. The two experiments were carried out in a commercial orchard cultivation of fig cv. Roxo-de-Valinhos - four years old, conducted in rainfed (without irrigation), being added regularly, bagasse in the tree rows as mulch (mulching) and intended to produce green fruit industry in the municipality of Caldas - MG. The experiment 3 (March 28th to July 28th, 2012) was installed in fig seedlings grown in full sun in the Departmento de Horticultura, Faculdade de Ciências Agronômicas, Campus de Botucatu, Universidade Estadual Paulista - UNESP, Botucatu-SP. Three experiments were conducted in a randomized block design, considering one control (no application) and one or two applications of trinexapac-ethyl, in seven concentrations in solution form: 0; 62.5; 62.5 + 62.5; 125; 125 + 125; 250; 250 + 250 and 500 mg L-1 of active ingredient, distributed in four blocks. The plot consisted of four plants and one plant surround on each side of the plot. In experiment 1 and 2, the first spray was in new branches (shoots) standardized to 50.0 cm in length and containing 12 internodes (around 12 axillary buds). The second spraying was performed in the same lines, 45 days after the first application. Already in experiment 3, the first spray was in new branches (shoots) with standard 26.0 cm in length and containing 16 internodes (around 16 axillary buds). The second spraying was performed in the same lines, 45 days after the first application. The use of trinexapac-ethyl, both in one as in two applications of 250 mg L-1 did not affect a more pronounced effect on growth, increased plant height, number of internodes, length of the branch and ...
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Dias, João Paulo Tadeu 1985. "Etil-trinexapac em diferentes concentrações e épocas de aplicações no crescimento de figueira (Ficus carica L) /." Botucatu :, 2014. http://hdl.handle.net/11449/103297.
Full textAbstract:
Orientador: Elizabeth Orika OnoBanca: João Domingos Rodrigues
Banca: Giuseppina Pace Pereira Lima
Banca: Terezinha de Fatima Fumis
Banca: Aparecida Conceição Boliani
Resumo: Neste trabalho foram realizados três experimentos com o objetivo de estudar o efeito do regulador vegetal, etil-trinexapac, no crescimento e produção da planta de figueira (Ficus carica L.). O experimento 1 foi desenvolvido no período de 27 de agosto de 2011 a três de março de 2012 e o experimento 2, de 27 de agosto de 2012 a três de março de 2013. Os dois experimentos foram implantados em pomar comercial de cultivo de figueira cv. Roxo-de-Valinhos com quatro anos de idade, conduzidos em sequeiro (sem irrigação), sendo adicionados, regularmente, bagaço de cana nas linhas das plantas como cobertura morta (mulching) e destinando a produção de frutos verdes à indústria, no município de Caldas-MG. O experimento 3 (28 de março a 28 de julho de 2012) foi instalado em mudas de figueira cultivadas a pleno sol no Departamento de Horticultura, da Faculdade de Ciências Agronômicas do Campus de Botucatu da Universidade Estadual Paulista - UNESP, Botucatu-SP. Os três experimentos foram instalados em delineamento de blocos casualizados, considerando uma testemunha (sem aplicação) e, uma e duas aplicações de etil-trinexapac, em sete concentrações, na forma de solução: 0; 62,5; 62,5 + 62,5; 125; 125 + 125; 250; 250 + 250 e 500 mg L-1 de ingrediente ativo, distribuídos em quatro blocos. A parcela foi constituída por quatro plantas e uma planta de bordadura de cada lado da parcela. No experimento 1 e 2, a primeira pulverização foi realizada em ramos novos (brotações) padronizados com 50,0 cm de comprimento e contendo 12 entrenós (em torno de 12 gemas axilares). A segunda pulverização foi realizada nos mesmos ramos, 45 dias após a primeira aplicação. Já no experimento 3, a primeira pulverização foi realizada em ramos novos (brotações) padronizados com 26,0 cm de comprimento e contendo 16 entrenós (em torno de 16 gemas axilares). Já a segunda pulverização foi realizada nos mesmo ...
Abstract: In this work three experiments was to study the effect of the plant growth regulator, trinexapac-ethyl, on growth and yield of fig plant (Ficus carica L.). The experiment 1 was conducted during August 27th, 2011 to March 3th, 2012 and experiment 2, August 27th, 2012 to March 3th, 2013. The two experiments were carried out in a commercial orchard cultivation of fig cv. Roxo-de-Valinhos - four years old, conducted in rainfed (without irrigation), being added regularly, bagasse in the tree rows as mulch (mulching) and intended to produce green fruit industry in the municipality of Caldas - MG. The experiment 3 (March 28th to July 28th, 2012) was installed in fig seedlings grown in full sun in the Departmento de Horticultura, Faculdade de Ciências Agronômicas, Campus de Botucatu, Universidade Estadual Paulista - UNESP, Botucatu-SP. Three experiments were conducted in a randomized block design, considering one control (no application) and one or two applications of trinexapac-ethyl, in seven concentrations in solution form: 0; 62.5; 62.5 + 62.5; 125; 125 + 125; 250; 250 + 250 and 500 mg L-1 of active ingredient, distributed in four blocks. The plot consisted of four plants and one plant surround on each side of the plot. In experiment 1 and 2, the first spray was in new branches (shoots) standardized to 50.0 cm in length and containing 12 internodes (around 12 axillary buds). The second spraying was performed in the same lines, 45 days after the first application. Already in experiment 3, the first spray was in new branches (shoots) with standard 26.0 cm in length and containing 16 internodes (around 16 axillary buds). The second spraying was performed in the same lines, 45 days after the first application. The use of trinexapac-ethyl, both in one as in two applications of 250 mg L-1 did not affect a more pronounced effect on growth, increased plant height, number of internodes, length of the branch and ...
Doutor
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Tenreira, Tracey. "Contrôle génétique et moléculaire du stolonnage : Balance entre reproduction sexuée et multiplication végétative chez le fraisier diploïde." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0415.
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Le fraisier diploïde (Fragaria vesca, 2x=14) comporte deux modes de reproduction : la reproduction sexuée via la floraison, et la multiplication végétative via la production de stolons. Cette espèce présente également deux types de floraison, non-remontants ou remontants, selon la période d’initiation florale du génotype. Chez le fraisier diploïde, le gène responsable de la remontée florale a été identifié comme étant l’homologue du répresseur floral TFL1 et celui du stolonnage reste inconnu. L’objectif de cette thèse est d’identifier le gène responsable du stolonnage et de mieux comprendre la balance entre les deux modes de reproduction, sexuée et asexuée, chez le fraisier diploïde. Une approche de cartographie fine associée à du NGS a permis d’identifier le gène responsable du stolonnage, FvGA20ox4. Ce gène intervient dans la voie de biosynthèse des gibbérellines. Les génotypes non-stolonnants présentent une délétion de neuf bases qui ne modifie pas le cadre de lecture du gène. L’observation cytologique des méristèmes axillaires montre que les génotypes mutés présentent un allongement des axillaires comme les génotypes sauvages mais que ces bourgeons nécrosent par la suite. Une étude de l’activité enzymatique de la protéine délétée de trois acides aminés a montré qu’elle était inactive et ne permettrait pas de transformer les précurseurs de GA (GA12) en GA intermédiaires, qui seront convertis en GA actives via d’autres enzymes. Chez les génotypes mutés, un apport de GA3 permet de restaurer l’émergence de stolons. L’étude de la balance entre les deux modes de reproduction a été étudiée au sein d’une population en ségrégation pour le stolonnage et la remontée florale. Une approche QTL a permis de confirmer le rôle des gènes TFL1 et GA20ox4 dans le devenir des méristèmes en floral ou stolon respectivement et d’identifier deux loci présents sur le LG3 et LG4 impliqués dans la variation quantitative de la floraison ou du stolonnage respectivement. Pour le stolonnage, une interaction forte entre TFL1 et GA20ox4 a été mise en évidence par ANOVA. De plus, le suivi hebdomadaire de cette population pendant deux ans a montré que le processus de remontée florale prédominait celui de stolonnage. En conclusion, les données obtenues permettent une meilleure compréhension du stolonnage et de la balance entre les deux modes de reproduction chez le fraisier diploïdeThe diploid woodland strawberry (2n=2x=14) is a good model for genetic and genomic studies since it presents a small genome completely sequenced and its generation period is short. This species displays two modes of reproduction, sexual with flowering and vegetative through runnering, which is the capacity to form stolon. In addition, this species displays contrasted genotypes for their variation of flowering length because of difference in the period of floral initiation. This trait is under the control of TFL1. However, the genetic and molecular control of vegetative reproduction is poorly understood as the one of the balance between the two modes of reproduction. The objective of this work was to characterize the gene responsible of runnering and to decipher genetically and physiologically the balance between the two modes of reproduction. By developing a strategy combining linkage map, bulks and NGS, we found that runnering is controlled by the gibberellin (GA) oxidase, FvGA20ox4. The loss of runnering function is caused by a deletion of nine nucleotides, which does not change the open reading frame of the RNA and leads to a protein shortened by three amino acids. The GA oxidase activity was confirmed in enzymatic activity assays with recombinant protein. In addition, the loss-of-function can be restored by exogenous GA3 application. The genetic architecture of the balance between two reproductive modes, sexual and vegetative, was deciphered based on QTL approach. Results showed that, beside the known roles of TFL1 and GA20ox4 genes in promoting perpetual flowering and runnering processes respectively, two loci localized on LG4 and LG3 were linked to the quantitative responses of these processes. In addition, TFL1 and GA20ox4 genes showed epistatic interaction, and the process of flowering was maintained as priority over runnering, which decreased. These results provided new insight in the genetic control of the relationship between sexual and vegetative reproduction
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Regnault, Thomas. "Biosynthèse et transport des gibbérellines chez Arabidopsis thaliana." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ098/document.
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Les gibbérellines (GA) sont une classe de phytohormones modulant différents aspects du développement des plantes. La biosynthèse des GA est catalysée par l’activité de différentes classes d’enzymes permettant la formation des formes bioactives. Si les mutants de biosynthèse sont nains, un excès de l’hormone provoque croissance excessive et stérilité. Ainsi, les plantes ont développé des mécanismes efficaces leur permettant de maintenir une concentration optimale de GA bioactives. Un niveau supplémentaire de régulation peut être constitué par une séparation spatiale de la biosynthèse dans différents types cellulaires et organes. A l’aide d’approches variées, nous démontrons qu’une forme intermédiaire est mobile sur de longues distances. Ce transport s’effectue à travers les vaisseaux vasculaires de la plante, et pourrait impliquer des transporteurs. Ensembles, nos résultats révèlent la nature et les propriétés biologiques du transport de GA sur de longues distances chez ArabidopsisGibberellins (GA) are a class of diterpenoid hormones regulating major aspects of plant growth. GA biosynthesis from GGDP is catalyzed by the activity of different classes of enzymes leading to the formation of the active forms of GA. Thus GA biosynthesis mutants are dwarfs and late flowering, while GA overdose causes excessive growth and sterility. Therefore plants have evolved efficient mechanisms to maintain optimal levels of bioactive GA. However, an additional level of regulation may reside in the separation of the GA biosynthetic pathway into distinct cell types and organs. Through micro-grafting, genetic and biochemical approaches, we demonstrate that a GA intermediate is mobile over long distances in Arabidopsis. Moreover, this transport occurs through vascular tissues of the plant, and may involve specific transporters. Altogether, our results reveal the nature and the biological properties of GA long distances transport in Arabidopsis
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Fonouni-Farde, Camille. "Le rôle des gibbérellines dans la régulation de l’architecture racinaire chez la légumineuse modèle Medicago truncatula." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS079.
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L’architecture du système racinaire des légumineuses est déterminée par la croissance des racines et leur capacité à former des racines latérales et des nodosités symbiotiques fixatrices d’azote en fonction des conditions environnementales. Chez la légumineuse modèle Medicago truncatula, nous avons mis en évidence que les phytohormones gibbérellines (GAs) et leur voie de signalisation – médiée par trois protéines MtDELLAs présentant des profils d’expression redondants – jouent un rôle clé dans la régulation du développement du système racinaire. En conditions non-symbiotiques, les GAs régulent négativement la croissance racinaire en réprimant l’activité méristématique et l’élongation cellulaire, et inhibent la formation des racines latérales. En conditions symbiotiques, le rôle des GAs et de leur voie de signalisation est double : au niveau de l’épiderme, les protéines MtDELLAs régulent positivement l’infection par les bactéries symbiotiques Rhizobia en interagissant de façon directe avec la voie de signalisation des facteurs Nod bactériens. Au niveau du cortex, les GAs régulent négativement l’organogénèse des nodosités. Les phytohormones cytokinines (CKs) et leur récepteur MtCRE1 étant essentiels pour initier la nodulation, l’interaction entre les voies de signalisation GA et CK a été analysée en parallèle. Les CKs régulent le niveau de GAs bioactives en modulant l’expression des gènes de leur métabolisme de manière dépendante du récepteur aux CKs MtCRE1. Réciproquement, les GAs régulent les gènes du métabolisme CK et le niveau de CKs bioactives de manière dépendante des MtDELLAs. Par ailleurs, une forme activée de MtDELLA complémente partiellement le phénotype de nodulation du mutant cre1 et lie le promoteur de MtCRE1, indiquant que les voies de signalisation GA et CK régulent la nodulation en étroite associationLegume root system architecture is determined by both root growth and their ability to form lateral roots and nitrogen-fixing symbiotic nodules, depending on environmental soil conditions. In the model legume Medicago truncatula, we have shown that the phytohormones gibberellins (GAs) and their signaling – involving three MtDELLA proteins with redundant expression patterns – play a crucial role in the regulation of the root system development. In non-symbiotic conditions, GAs negatively regulate root growth through the repression of meristematic activity and cell elongation, and inhibit lateral root formation. In symbiotic conditions, GA and their signaling pathway play a dual role: in the root epidermis, MtDELLA proteins positively regulate infection by symbiotic bacteria Rhizobia, by directly interacting with the bacterial Nod factor signaling pathway. In the root cortex, GAs negatively regulate nodule organogenesis. The phytohormones cytokinins (CKs) and their receptor MtCRE1 being essential for the initiation of nodulation, we additionally analyzed the crosstalk between GA and CK signaling. CKs regulate the bioactive GA pool, controlling the expression of GA-metabolic genes, depending on the MtCRE1 receptor. In turn, GAs regulate CK-metabolic genes and the bioactive CK pool, depending on MtDELLAs. In addition, a dominant version of a MtDELLA partially complements the nodulation phenotype of the cre1 mutant and binds to the MtCRE1 promoter. These results indicate that GA and CK signaling pathways closely interact to regulate nodulation
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Saint, Germain Alexandre de. "Vers une meilleure compréhension du mode d’action des strigolactones et de leur interaction avec les autres hormones du développement." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112326/document.
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L'étude de la ramification chez le pois, à partir des mutants hyper-ramifiés ramosus (rms) a permis de mettre en évidence l'existence d'une nouvelle famille d'hormones végétales : les strigolactones, inhibant la ramification des plantes à graines. La découverte de cette hormone végétale ouvre de nouvelles pistes de recherche sur la biosynthèse et la perception de cette nouvelle hormone. Nous avons montré le rôle du gène PsBRC1, codant un facteur de transcription de type TCP et homologue du gène TEOSINTE BRANCHED1 du maïs, dans la voie de signalisation des strigolactones. L’étude de ce gène nous a permis d'avoir une meilleure compréhension de l’interaction entre strigolactones et cytokinines dans le contrôle de la ramification, de la dynamique de la levée de dormance des bourgeons axillaires, et d'effectuer les premières études de relations structure-activité des strigolactones sur l’inhibition de la ramification chez le pois.Nous avons étudié et caractérisé d'autres éléments dans la voie de signalisation. Chez le pois, deux mutants, autres que Psbrc1, ne répondent pas à l’application de strigolactones, rms3 et rms4. Le gène RMS4 code pour une protéine à boîte F. Nous nous sommes focalisés ici sur le mutant hyper-ramifié rms3. Nous avons montré que RMS3 est l'homologue du gène D14 du riz, codant pour une protéine de la superfamille des α-β/hydrolases. Ces protéines peuvent avoir une activité enzymatique et ainsi pourraient modifier les strigolactones en un composé actif. Le récepteur des gibbérellines GID1 appartient aussi à cette famille, RMS3 est donc un bon candidat pour être le récepteur des strigolactones. Nous avons utilisé une strigolactone radiomarquée afin d’étudier le métabolisme de l'hormone. Nous avons découvert que la strigolactone synthétique, 3H-GR24 est clivée en un composé inconnu au contact des racines, indépendamment de l'activité de la protéine RMS3. Ce composé de structure inconnue se retrouve aussi dans la sève du xylème alors que 3H-GR24 y est absent.Outre un phénotype hyperbranché les mutants rms présentent une diminution de la taille de leurs entre-nœuds, qui n'est pas due à l’augmentation de la ramification. Nous avons étudié l'origine du nanisme des mutants déficients en strigolactones et affectés dans la réponse à l’hormone. Des approches génétiques et moléculaires ont été utilisées pour tester une interaction possible entre les strigolactones et les gibbérellines. Nous avons montré que les strigolactones régulaient l’élongation des entre-nœuds indépendamment des gibbérellines.Le pois est un excellent modèle en génétique et en physiologie. Avec le développement de nouvelles techniques à l'INRA (TILLING; UNIGENE : ensemble de plus de 40000 séquences exprimées de pois), nous avons pu identifier de nouveaux gènes de biosynthèse des strigolactones chez le pois et obtenir plusieurs nouveaux mutants de pois. Ces mutants seront essentiels pour les futures études du laboratoire et pourront permettre d'identifier de nouveaux intermédiaires dans la biosynthèse et le métabolisme des strigolactonesThe study of shoot branching in pea, using the high branching ramosus (rms) mutants has highlighted the existence of a new family of plant hormones: the strigolactones, inhibiting shoot branching in seed plants. The discovery of this novel plant hormone opens novel research areas in the deciphering of strigolactone biosynthesis and strigolactone perception. We have shown the role of the pea TCP transcription factor, PsBRC1, the homolog of the maize TEOSINTE BRANCHED (TB1) in strigolactone signaling. The PsBRC1 gene was shown to have a role in integrating strigolactone and cytokinin pathways, and allowed to have a better understanding of the dynamics of bud outgrowth, and to perform the first strigolactone Structure-Activity Relationship studies for branching inhibition in pea. We investigated and characterized other elements in the signaling pathway, including the strigolactone receptor. In pea, two mutants, other than Psbrc1, do not respond to the application of strigolactones, rms3 and rms4. The RMS4 gene encodes an F-BOX protein and here we focused on the high branching rms3 pea mutant. We have shown that RMS3 is the homolog of the rice D14 gene encoding a protein of the α-β/hydrolase superfamily. Consequently RMS3 may have an enzymatic activity to modify strigolactone into an active compound. The gibberellin receptor GID1 also belongs to this family, therefore RMS3 is also a good candidate for the strigolactone receptor. We used a radiolabeled synthetic strigolactone, 3H-GR24, to investigate the metabolism of the hormone. We discovered that the synthetic strigolactone, 3H-GR24 is cleaved in an unknown compound in the root media independently of RMS3 activity, compound which is also found in the xylem sap in contrast to 3H-GR24. The rms mutants exhibit not only a high branching phenotype but also a reduced height which is not due to this high branching. We investigated the origin of the dwarfism of strigolactone-deficient and response mutants in pea. Genetic and molecular approaches have been used to test a possible interaction between strigolactones and gibberellins. We have shown that strigolactones regulate stem elongation independently of gibberellin. Pea is a powerful model plant for genetics and physiology. With the development of new facilities at INRA (TILLING; UNIGENE set of more than 40000 expressed sequences), we were able to identify new biosynthesis genes in pea and to obtain several novel pea mutants. These mutants will be essential for future studies of the laboratory in particular to identify new intermediates in strigolactone biosynthesis and metabolism
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Rader, Gaurakisora D. "Blame and the Side-Effect Effect." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1536758782159273.
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Harrison, Derek Laurie Shawn. "Bud development and the influence of gibberellins on the differentiation of reproductive buds in Pinus caribaea var. hondurensis." Phd thesis, 1987. http://hdl.handle.net/1885/143058.
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Hasan, O. "The effect of paclobutrazol on flowering activity and gibberellin levels in Eucalyptus nitens and Eucalyptus globulus." Thesis, 1993. https://eprints.utas.edu.au/17320/1/whole-Hasan-thesis.pdf.
Full textAbstract:
Experiments prior to this project demonstrated the capacity of the plant growth
retardant paclobutrazol to enhance flowering in commercially important Eucalyptus
nitens and E. globulus trees and produced anecdotal evidence of this material
reducing time to first flowering. Paclobutrazol is known to reduce the levels of
endogenous gibberellins (GAs) in several species and hence it was hypothesized
that the effects of paclobutrazol on flowering in these Eucalyptus species may be
mediated by an effect on GA levels. The lack of previous identification of GAs in
this genus necessitated the development of extraction and purification procedures to
identify and quantify GAs. The compounds identified suggested that the early 13-
hydroxylation pathway was the dominant mechanism for production of GAs, with
GA 1 as the likely biologically active compound. Persistence of a paclobutrazol
induced increase in flowering of grafted E. nitens material was related to the
continued depression of endogenous GA concentrations. Additionally, higher
concentrations of GA1 were found to be correlated with reduced flowering
responses in this reproductively competent material. A lowering of endogenous
GA levels, in combination with a co-requisite of a period of cold has been
associated with the induction of first flowering in newly grafted E. nitens material.
The effects of cold treatment were not mediated by an effect on levels of GA1 or
GA2o·
Soil applied paclobutrazol was shown to travel up stems and accumulate in leaf
tissue. Breakdown in plant tissue was shown to be rapid, with a half-life likely to
be substantially less than 21 d. Soil and foliar application methods were shown to
produce different patterns of metabolism of labelled paclobutrazol, as demonstrated
by HPLC separation of labelled metabolites extracted from growing apices. The
rate of breakdown in the soil was observed to be variable, but slow in comparison
to that within plant tissues and may be the source of the considerable persistence of
effects of paclobutrazol application observed in some field trials.
Application of paclobutrazol to 6 month old E. globulus seedlings resulted in
the production of flower buds at less than 18 months of age despite the retention of
juvenile foliage. One year later, following normal bud development, anthesis and
pollination, capsules were produced, while maintenance of material in a range of growth conditions over the second winter again demonstrated the strong
requirement for cold seen in grafted E. nitens, as well as revealing an apparent
promotion of flowering associated with reduced pot size. The reduction in
generation time achieved using commercial seedlings was ca. 50% (3 years) which
should be of major benefit to tree breeders, given that the long generation time of
eucalypts is a major determinant of the rate at which genetic gains can be made by
conventional tree breeding methods. In reproductively competent seedlings and
grafts, paclobutrazol application was confirmed to increase the average number of
flower buds per seedling. This could be advantageous when seed requirements
from an elite tree are high, or when yearly seed yield tends to be variable.
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Ritchings, Bruce W. "Two studies on the developmental biology of the corngrass (Cg) mutation of maize (Zea mays L.) 1) the response of corngrass to exogenous application of two gibberellins : 2) the effect of daylength and temperature on expression of the corngrass phenotype /." 1987. http://catalog.hathitrust.org/api/volumes/oclc/17472635.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1987.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 96-100).
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Kleingeld, Gerhard. "A comparison between the efficacy of radionically prepared gibberellic acid and homoeopathically prepared gibberellic acid (GHP) on the germination rate and seedling development of barley seeds." Thesis, 2016. http://hdl.handle.net/10321/1508.
Full textAbstract:
Submitted in partial compliance with the requirements of the Master’s Degree in Technology: Homoeopathy, Durban University of Technology, Durban, South Africa, 2016.Aim The aim of this controlled, experimental study was to compare the biological activity of various homoeopathic potencies of gibberellic acid manufactured radionically (AMS transfer device) and conventionally (GHP) in terms of their respective influence on germination rate and seedling development of barley seeds; all the respective results being contrasted against those produced by the distilled water control. Methodology The research was completed by employing quantitative research techniques and followed true experimental design. Homoeopathically (Hahnemannian) prepared gibberellic acid followed the manufacturing guidelines of method 5a involving liquid preparations, as specified in the German Homoeopathic pharmacopoeia (GHP) (Benyunes 2005). A second radionic ‘equivalent’ version of each of the Hahnemannian potencies was manufactured using the ‘AMS wave transfer’ device. Four sources of data were collected namely, germination count and rate, seedling development (root length), seedling dry mass, and number of seeds with measurable roots. All the data was collected and documented on a data collection sheet using Microsoft Excel. All the data was statistically analysed and subjected to analysis of variance (ANOVA) using GenStat Version 14 (VSN International, UK) at the 5% level of significance. The statistical data was used to produce a comparison between the different remedies and distilled water. Results All of the remedy treatment groups (Radionic 200c, Hahnemannian 200cH, Radionic 4c and Hahnemannian 4cH) displayed suppressive effects (to certain extents respectively ) on seed growth and development in comparison to the control group (distilled water). The control group displayed greater seedling development in comparison to all remedy treatment groups which was most evident in the average root lengths and high vigour seed lot root lengths having longer roots than all remedy treatment groups. The control group also displayed a higher number of seeds with measurable roots compared to all the remedy treatment groups in both total number of seeds and in the seeds accounted for in the high vigour lots. This suggests that all Homoeopathic remedies irrespective of potency or manufacture method (Radionic or Hahnemmanian) had similar suppressive effects on root growth and seedling development and this suppressive effect was in turn not evident in the control group. Conclusion The experiment results suggest that radionically manufactured homoeopathic remedies (AMS wave transfer device) have similar biological effects (suppressive effects) to the equivalent Hahnemannian manufactured homoeopathic remedies, although further research in this field is necessary to confirm these findings the results from this study are supportive of the use of radionically prepared remedies in homoeopathic practice.
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