Call number: LD2668 .T4 1986 V47 / Master of Science / Biochemistry and Molecular Biophysics Interdepartmental Program

Orientador: Adalton Mazetti Fernandes / Banca: 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

Abstract Gibberellins (GAs) are a class of plant hormones that regulate many aspects of plant growth and development including seed germination, stem elongation and fruit development. To investigate the regulation of GA biosynthesis and the impact of altered GA levels on plant growth and development, transgenic pea (Pisum sativum L. cv. Carneval) plants were generated to overexpress PsGA3ox1 (codes for GA 3-hydroxylase which converts GA20 to bioactive GA1) under the control of the CaMV-35S promoter. Increased expression of the transgene PsGA3ox1 was correlated with altered plant phenotype including longer internodes, larger stipules and tendrils, and longer pods. Transgenic lines also showed upregulation of the GA catabolic genes PsGA2ox1 and/or PsGA2ox2, suggesting that GA1 substrate-induced feedback regulation also occurs to maintain GA homeostasis. Changes in endogenous GAs, quantified using an isotope dilution method, indicated that an increased flux in GA biosynthesis occurred in the expanding internodes, stipules and tendrils of the PsGA3ox1-overexpressor lines. Higher bioactive GA1 levels and growth were correlated with lower PsGA2ox1 transcript levels in elongating internodes, and oscillation of these parameters between adjacent elongating internodes in the PsGA3ox1-overexpression lines suggests that coordination of bioactive GA levels and growth occurs between adjacent internodes. During germination and early seedling growth, GA gene expression studies suggested that PsGA3ox1-overexpression increased the flux through to bioactive GA in the cotyledons, shoots and roots of pea seedlings, resulting in longer shoots but shorter roots. Auxins are a class of plant hormones involved in growth and differentiation of plants that can influence GA biosynthesis and action. The location and action of auxins is in part regulated by auxin carrier proteins. The expression patterns of the putative auxin efflux carrier genes PsPIN1 and PsPIN2 in elongating internodes were correlated with vascular re-patterning events in this tissue, and PsGA3ox1-overexpression appears to increase internode PsPIN1 and PsPIN2 transcript abundance and the formation of the vascular connections between the internode and the axillary buds. Overall, characterization of PsGA3ox1-overexpressor lines in pea demonstrated that bioactive GA levels are tightly regulated in pea tissues for the coordination of plant growth and development. / Plant Science

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Bibliography: leaves 194-229 / xviii, 229, [30] leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Physiology, 1984

Thesis (M.Ag.Sc. )--University of Adelaide, Dept. of Plant Physiology, 1965. / Typecript. Includes bibliographical references.

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