Typewritten Bibiography: leaves 209-222.

Graduation date: 1998

Typewritten / Bibiography: leaves 209-222. / iv, 223 leaves : ill. ; 26 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 Botany, 1960

Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains viii, 70 p. : ill. Includes abstract. Includes bibliographical references (p. 64-70).

Vita. / Digitized by Kansas Correctional Industries

Thesis (MSC.Agriculture)) --University of Limpopo, 2009. / The aim of this experiment was to evaluate the effect of moisture stress on tomato, using non-destructive remote sensing techniques and agronomic traits under field and greenhouse conditions. Two tomato cultivars Roma VF and Flora Dade were used for the trial. The soil was fertilized optimally for all nutrients to avoid other stresses except water stress; a 2x2 factorial experiment was conducted using two levels of water regimes (stressed vs. control (non-stressed)) having four replicates and two cultivars using a Completely Randomized Design. Pots were put under greenhouse and field conditions. Canopy temperature was measured using an infrared thermometer, NDVI values were recorded using a green seeker hand-held optical sensor unit and stomatal opening were determined using a leaf porometer. Other agronomic traits including days taken for 50% flowering, plant height, number of fruits per plant and fruit yield per plant were recorded. Leaf temperature in stressed plants was high as compared to non-stressed plants, whereas NDVI and stomata conductance values were low. Number of fruits per plant was low; each plant had 4.00 fruits under field conditions and 5.00 fruits per plant under greenhouse conditions as compared to 9.00 fruits under field conditions and 13.00 under greenhouse conditions for non stressed plants. Stressed plants were shorter as compared to non-stressed plants and days taken for 50% flowering were delayed in both cultivars for stressed plants. Stressed plants showed a sign of stress at early stages of plant development. Most of these signs were found on the plants rather than on the fruits, the shape of the main stem of a growing plant was one of the good indicators as it became thin and stringy under stressed conditions. The experiment showed that it is possible to evaluate the effect of moisture stress on tomato by the use of canopy temperature, NDVI, stomatal conductance and agronomic traits.

The phytohormones auxin and cytokinin control plant development through a complex network of interactions which include synergistic, additive, and opposite effects whose mechanisms are unknown. The auxin-insensitive diageotropica (dgt) mutant provided a tool to dissect the relationship between auxin- and cytokinin-induced responses in tomato. Morphological, physiological, and molecular data support the proposal that auxin and cytokinins control a common set of developmental processes through separate signal transduction pathways which interact downstream from the DGT gene product. Morphological traits of dgt plants, such as reduced root and shoot growth, reduced leaf complexity, and reduced apical dominance were phenocopied by exogenous cytokinin application to wild-type plants, demonstrating that cytokinins and the DGT-mediated auxin response control a common set of phenotypic characteristics. Because the dgt mutation had no detectable effects on the levels of endogenous cytokinins or on the cytokinin sensitivity of whole plants, cytokinins were hypothesized to cause dgt-like effects on plant development through inhibiting auxin-induced responses. This hypothesis was supported by physiological experiments showing that auxin-induced elongation and ethylene synthesis were inhibited in cytokinin-treated wild-type and in untreated dgt hypocotyls. Differences between the effects of cytokinins and the dgt mutation on auxin responses became apparent at the molecular level. Experiments on the auxin-induced accumulation of transcripts for two ACC-synthase genes and one SAUR gene demonstrated that cytokinin treatment selectively reduced the auxin-induced expression of only one ACC-synthase gene, while the dgt mutation inhibited the auxin-inducibility of all three genes. The effects of the dgt mutation were thus more pleiotropic than the cytokinin effects, suggesting that cytokinins inhibit auxin-responses downstream from the DGT gene product. In vitro culture of dgt hypocotyl explants and calli demonstrated shared or interacting signal transduction pathways for auxin and cytokinin in the stimulation of cell division, and independent pathways for the control of organ regeneration and vascular differentiation. / Graduation date: 1997

Call number: LD2668 .T4 1978 A45 / Master of Science

The Granger causality test was used to explore the price interdependence in the wholesale tomato markets of Fortaleza, Teresina and Sao Luis in the Northeast of Brazil. Following the results of this study, the conclusion is reached that, in general terms, the prices in these markets are established efficiently implying a competitive environment in the Northeast tomato markets. Fortaleza operates as a leading market "driving" the prices of the Teresina and Sao Luis secondary markets.

Graduation date: 1994