Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Thesis (Ph. D.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Michael J. Giroux. Includes bibliographical references.

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Michael J. Giroux. Includes bibliographical references (leaves 58-61).

Thesis (M.S.)--Montana State University--Bozeman, 2004. / Typescript. Chairperson, Graduate Committee: Michael J. Giroux. Includes bibliographical references (leaves 50-54).

Thesis (Ph.D.)--Murdoch University, 2003. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 229-232.

Thesis (MScAgric)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (MSc Natural and Agricultural Sciences)--University of Pretoria, 2007. / Includes bibliographical references. Summary in English.

Seedlings of Triticum aestivum L. cv. Maris Huntsman were grown for 7 days in a controlled environment chamber (16 hour photoperiod: PAR - photosynthetically active radiation), in the presence and absence of ultraviolet-B (UV-B: 280-320nm) radiation (+30% increase on ambient). UV-B resulted in a 17% reduction in leaf length due to changes in both the rate and duration of cell division and elongation. Measurements of the spatial distribution of cell division and elongation within the primary leaf were used to determine the temporal distribution of cells (i.e. cell age). The cell age gradient allows for the comparison of direct, and indirect UV-B responses, which result from the altered growth. Direct effects of UV-B included a reduction in chloroplast and mitochondrial transverse area, and an increase in chloroplast number, which suggests that UV-B affects organelle division. The developmental changes in protein content and amino acid free pools were increased as a direct result of UV-B treatment. In contrast, increases in chlorophyll content were due to an indirect effect of UV-B via altered growth. UV-B had no effect on the developmental changes in photosynthetic capacity and efficiency, and carbohydrate status of the primary leaf The primary leaf of wheat has provided a model system in which to examine the effects of UV-B on leaf development. This study highlights the need to consider cell age when determining the response of plants to UV-B.

Seedlings of Triticum aestivum L. (cv Maris Huntsman) were propagated in a controlled environment chamber to 240hr (post-imbibition) under ambient, enhanced UV-B (200Wm-2), CO2 (550ppm and 700ppm) and combined UV-B/CO2 treatments. The grass leaf developmental model was used to determine changes in the cell-age gradient along the leaf length, under these treatments. By full leaf expansion, enriched CO2 had significantly increased leaf height, whilst this was decreased under enhanced UV-B, and decreased further under the combined UV-B/CO2 treatment. Analysis of the zones of cell division and cell elongation at the leaf base established that enriched CO2 increased mitotic activity and more so, cell elongation rates, whilst enhanced UV-B predominantly extended the duration of the cell division cycle. Under the combined UV-B/CO2 (550ppm) treatment it is proposed that cell division and cell elongation are greatly reduced at leaf emergence, but CO2-induced increases of cell division rates occur over time, prior to early cessation of leaf growth. The reduced leaf cell supply under enhanced UV-B+/-CO2 was accompanied by reductions in chlorophyll and protein synthesis at the leaf base, more so on a cell-age basis. Enhanced UV-B+/-CO2 did not alter the leaf Rubisco content. However, coleoptile Rubisco content was significantly reduced under enhanced UV-B, but this effect was ameliorated in combination with CO2. Large increases in UV-B-absorbing compounds accumulated along the leaf under enhanced UV-B+CO2 (550ppm), although this was attributed primarily to altered cell-age gradients rather than to UV-B induction per se. Analysis by Differential Display Reverse Transcription-PCR of the cell division zone has led to the isolation of 19 up-regulated and 11 down-regulated putative UV-B responsive transcripts. It is believed that the use of DDRT-PCR will further elucidate specific plant responses under these treatments.

Thesis (M. Sc.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on Jan. 26, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Agricultural and Resource Economics, Department of Rural Economy, University of Alberta. Includes bibliographical references.