Thesis (M.S.)--Brigham Young University. Dept. of Plant and Animal Sciences, 2006. / Includes bibliographical references.

Proefschrift--Utrecht. / Bibliography: p. [123]-129.

Title from PDF of title page (University of Missouri--Columbia, viewed on February 24, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Dale Blevins. Vita. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 62-63.

Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 37-38). Also available via Humboldt Digital Scholar.

Cissampelos capensis L. f. (Menispermaceae) commonly known as “Mayisake” (Xhosa) and “Dawidjieswortel” (Afrikaans) is the most commonly used medicinal plant of the Menispermaceae family in South Africa. The rhizomes of Cissampelos capensis are the most used part of the plant to treat illnesses. This poses a threat to the ongoing conservation of this valuable endemic species. Thus, we studied the chemical variation and subsequently the bioactivity in the stems and rhizomes of Cissampelos capensis, the Eastern Cape medicinal plant, to suggest the possible use of the stems for medicinal purposes. We studied the variation in the chemical composition in the stems and the rhizomes by employing four different extraction methods; the methanolic-, non-polar-, alkaloidal- and Total Tertiary Alkaloidal (TTA) to extract compounds from Cissampelos capensis. Employing various chromatographic techniques, HPLC, NMR and LC/MS to investigate the chemical variation and the in vitro assays for the crude materials of the stems and rhizomes of Cissampelos capensis. We successfully documented a library of the phytochemicals content in Cissampelos capensis from three different regions in the Eastern Cape. We could profile different extraction methods, with the TTA extraction delivering the best comparative profile. Employing LC/MS and HPLC we identified eleven known alkaloidal compounds in the stems and rhizomes. We also isolated a known alkaloid, pronuciferine, from the TTA extract and a crystal structure of proto-quericitol from the methanolic extract, which was isolated for the first time from Cissampelos capensis. Preliminary in vitro results suggested anti-inflammatory activity in the methanolic extracts of the stems and rhizomes, while the TTA extracts showed some cytotoxicity. Finally, through analytical HPLC analysis this study found as high as 31% similarity between the chemical variation of the stems and rhizomes, but key alkaloids were not always present, indicating more work is needed before the stems can be recommended as a replacement for the rhizomes.

No description available.

A passive system that may be useful for measuring electrochemical changes occurring in in vivo, extracellular plant tissue has been developed within the past few years. The technique involves the placement of a small (250 μm diameter) noble metal probe into the anatomical region of interest. The electrode potential of this probe is then established relative to a reference electrode. The time variation of this potential (up to 100 mV or more per day) is termed an electrophytogram. The changes are coherent and reproducible. In this dissertation theoretical physiological bases for the voltage fluctuations have been developed. One theory involves modeling the electrophytogram as a chemical thermodynamic system passing through a series of "frozen" equilibria. The electron is considered as the chemical species of interest in this system and changes in the redox potential are interpreted in terms of an electron electrochemical potential (μ̃ₑ).The relationship between changes in the electrochemical nature of the solution contiguous with the probe and the μ̃ₑ intensity variable is then represented for several limiting cases. In the case of a redox reaction accompanied by a proton exchange, the limiting equation shows that pH changes well within the physiological range for extracellular plant fluid can account for the observed voltage fluctuations. An alternative representation of the electrophytogram as an electrostatic field phenomenon is more difficult to analyze due to a lack of information about the three dimensional structure and the probe/tissue interface. However, a cylindrical capacitor model shows that fluxes in the range of a few hundred monovalent ions per um³ of extracellular volume could easily explain the measured voltage changes. The third model involves the polyelectrolyte gel nature of the plant cell wall. The electrophytogram voltage signal is considered to result from surface interactions between the metal probe and the cell wall. This interaction is analyzed by using the theory of interacting electrochemical double layers. Output from a computer simulation shows that if these two surfaces approach within two Debye lengths, a voltage signal will be generated at the electrophytogram probe. Furthermore, slight fluctuations in the surface to surface distance result in voltage fluctuations of a magnitude equal to those observed in vivo. Physiological processes known to occur in plants are discussed with respect to the generation of electrochemical potential gradients and other physical conditions necessary to "drive" the various models. I conclude that the electrophytogram is most likely the result of surface interactions between the probe and the polyelectrolyte gel components of the cell wall. Elucidation of the physiological basis for electrophytograms must also involve an accurate anatomical interpretation of the position of the probe relative to the plant tissue. Therefore the results of a freeze-fracture electron microscopic (FFSEM) examination of the probe/tissue interface after wound healing are included. Electron micrographs show cell wall material appressed directly against the probe, indicating that the electrophytogram provides a method for monitoring the electrochemical status of the cell wall space. Since cell wall material is hygroscopic, it is reasonable to assume that the smallest probe/tissue separation distance observed in the FFSEM's represents a maximum in vivo value. Since this distance is less than 10nm, these data support the hypothesis that the metal surface is within two Debye lengths of the cell wall surface in vivo. Insertion of the probe into mature, fully elongated tissue appears to cause minimal damage to nonxylem tissue beyond the adjacent cell layers and virtually no damage to the xylem region.

The effects of fermentation on selected nutrients in the seed of the African locust-bean were investigated. The protein content of the seeds declined from 50.1% of dry weight in the unfermented sample to 32.4% of dry weight in the fully fermented sample. Methionine, cystine, and tryptophan were the limiting amino acids in the African locust-bean seed protein: the pattern of other essential amino acids was comparable to that of whole egg. Fermentation was accompanied by a decrease in seven essential amino acids. The riboflavin content of the seeds rose from 144.0 ug per 100 gm dry weight in the unfermented sample to 835.3 ug per 100 gm dry weight in the fully fermented sample. Thiamin content also increased with fermentation, from 31.3 up per 100 gm dry weight in the unfermented sample to 99.0 ug in the partially fermented sample; the thiamin content decreased with extended fermentation. Thus, fermentation enhanced both the riboflavin and thiamin content of the African locust-bean seed. Although there was some deterioration in protein quantity and quality, the fermented seed contains sufficient amounts of essential amino acids to supplement those provided by the staple cereal grains, if eaten in adequate amounts. / Graduation date: 1978

This thesis reveals trends in the fertilizer industry associated with the search for the most economical means for the production of plant nutrients, such as nitrogen, phosphorus and/or potassium compounds.