Published works [representing] original research conducted during the various phases of [his] academic development--Pref / Includes references / 1 v. (various pagings) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D. Sc.)--Faculty of Science, University of Adelaide, 1990

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Title from first page of PDF file (viewed March 18, 2010). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.

The chromosomes involved in twenty reciprocal translocations in G. hirsutum were reidentified by means of a specially designed crossing program. Each translocation line was crossed to appropriate monosomic, monotelodisomic, and/or translocation lines. The F₁ hybrids were then scored cytologically to verify the original chromosome identification. These twenty reciprocal translocations now become the cytogenetic tester set for G. hirsutum. Seed stocks for each verified translocation line will be maintained at, and distributed by, the University of Arizona. Nineteen of the twenty heterozygous translocations had a modal chiasma frequency per quadrivalent of four. Fourteen of these translocation lines formed predominantly ring multivalents at MI, and the remaining five translocations usually formed multivalents with at least one interstitial chiasma. One translocation line, which was originally produced by an interspecies cross, formed predominantly chains at MI. This increased amount of chaining in the quadrivalent is probably the result of interspecific chromosome material within the translocation reducing the chiasma frequency. The orientation of the centromeres in quadrivalents is influenced by the size of the chromosomes involved in the reciprocal translocation, and the constraints imposed by the chiasmata within the chromosome arms. Ten of the twenty reciprocal translocations studied formed predominantly alternate orientations at MI. Eight of these ten translocation lines were reciprocal translocations between two A subgenome chromosomes. This suggests that the large A subgenome chromosomes allow the quadrivalent to be more flexible, resulting in easy reorientation to the stable alternate configuration. Proximal chiasma formation influences the orientation and probable involvement of the homologous centromeres in spindle formation. Lines in which a high frequency of multivalents with interstitial chiasma were observed had a significantly lower frequency of multivalents with either one or two centromeres not involved in spindle formation of 3:1 orientations. In most of the heterozygous translocations, identification of each chromosome within the quadrivalent at MI was not possible. Estimation formulae were developed to estimate the positions of the breakpoints and the genetic lengths of each segment defined by multivalents in these translocations.

No description available.

A review of the literature established that there were areas of cytokinin transport which needed further investigation, in order to determine the function and/or mode of action of cytokinins during certain stages of plant development. Radioactive zeatin was applied to plant systems suitable for determining more about specific problems of cytokinin transport. The metabolism of the radioactive zeatin was monitored in relation to transport. The metabolism in, and possible export of, radioactive zeatin out of immature, mature and senescing Ginkgo biloba leaves was monitored using explants. The results showed that approximately the same percentage radioactivity was exported from the leaves at all three stages of their development. This indicates that these deciduous leaves could potentially export cytokinins, but the results were not regarded as being significant. Cytokinins would not have been expected to be transported out of expanding leaves, which rapidly utilize cytokinins, and in comparison greater cytokinin export would have been expected to occur from senescing leaves, but this did not occur. The resuIts could indicate that cytokinin glucosides in deciduous leaves are primarily inactivation products rather than storage compounds. The metabolism and transport of radioactive zeatin, applied to the leaves of Citrus sinesis trees, was monitored during the flush of new growth following a dormant period. Some of the radioactive zeatin applied to these leaves appeared to be utilized in the new shoot growth. This could imply that accumulated cytokinin glucosides in these evergreen leaves are exported out of the leaves and reutilized, and thus fulfil a storage function; although the extent to which export occurred as opposed to interconversion and/or catabolic metabolism in the leaves could not be determined. The distribution of radioactive zeatin applied to the xylem and phloem of Phaseolus vulgaris plants at three stages of development was also monitored. There appeared to be preferential transport of cytokinins in the transpiration stream, that is, applied to the xylem. The vegetative apices, buds and flowers appeared to be the major sinks for radioactive compounds in the vegetative and flowering plants, and the leaves were the most important sink in the fruiting plants. Radioactive zeatin in the phloem appeared to move passively with the assimilate stream. The transport of radioactive zeatin applied to the primary leaves appeared to confirm that cytokinins in the phloem were transported along with the assimilate stream. The results also indicated that the accumulated cytokinin glucosides in these annual leaves were primarily inactivation products, involved in regulating leaf metabolism, although some re-utilization of these cytokinins could potentially take place. could have reflected normal cytokinin transport occurring in the tissues. The main metabolic pathway, oxidation, did not, however, appear to be the main metabolic pathway in the plant tissues and may have been the result of the exogenous application of zeatin. The fact that metabolism did not appear to be the normal metabolism of the tissues, could potentially have affected transport. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1982.

Thesis (Ph. D.)--University of Canterbury, 2007. / Typescript (photocopy). "September 2007." Includes bibliographical references (p. 147-179). Also available via the World Wide Web.

Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Discipline of Plant and Pest Science, 2004? / Errata slip inserted at front. Includes bibliographical references (leaves 142-161). Also available online.

Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Discipline of Plant and Pest Science, 2004? / Title from screen page; viewed 8 Feb 2005. Includes bibliographical references. Also available in a print form.

Thesis (Ph. D.)--Simon Fraser University, 1976. / Includes bibliographical references (leaves 85-93).

Zea mays plants kept at ambient (ca 375ppm) and elevated CO₂ (ca 650 to 700ppm) were used to examine the possibility of a symplasmic loading, unloading and transport pathway in dark-adapted and illuminated (200μmolm⁻²sec⁻¹ ) sink and source leaves. 5,6-carboxyfluorescein diacetate was introduced into the mesophyll cells and symplasmic transfer observed 3h after application. In sink and source leaves exposed to ambient CO₂ and illuminated at 200 molm-2sec-1, the fluorescence front was observed approximately 3cm from the point of application, while in dark-adapted plants, the fluorescence front was observed approximately 1cm from the point of application. Under elevated CO₂ conditions the fluorescence front in illuminated plants appeared to transport faster moving approximately 5cm from the point of application, and in dark-adapted plants, only 3cm from the point of application. Based on the increase in 5,6-CF accumulation under elevated CO₂ conditions, the present study suggests that there was an increase in capacity for assimilate loading and transport under elevated CO₂ conditions. In source leaves, 5,6-CFDA was taken up into the mesophyll cells, loaded symplasmically and transported basipetally. In sink leaves 5,6- CFDA was taken up from basal mesophyll and after symplasmic loading, was transported acropetally where it was offloaded into the younger immature sink region. Transport in the sieve tubes was confirmed by using aniline blue, which was applied 3h after 5,6-CF transport. Aniline blue coupled with 5,6-CF transport studies showed that the sieve tubes of both cross and longitudinal veins are involved in symplasmic unloading, loading and transport processes in sink and source leaves. Apoplasmic uptake of 5,6-CFDA by cut leaves showed that after apoplasmic transport via the transpiration stream, 5,6-CFDA was offioaded to the xylem parenchyma where it was metabolically cleaved , releasing fluorescent 5,6-CF into the xylem parenchyma. Transverse sections cut after 3h of uptake were observed after 120 and 180 min suggesting that a retrieval of solutes occurs from the xylem to the xylem parenchyma, bundle sheath, phloem parenchyma and to the th in-walled sieve tubes. It was not possible to determine if the thick-walled sieve tubes were involved or if they took up 5,6-CF. Given the available data on loading and offioading of assimilates in sink and source leaves respectively, this study demonstrated that a slow symplasmic pathway exists from the mesophyll to the phloem, and that offloading from the phloem in sink leaves can occur via a symplasmic route.