Pacific and Pasifika Theses

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/4764

The theses listed in this collection were all completed at Massey University in a range of different departments and institutes. They have been included in this collection if the topic is strongly related to Pasifika/the Pacific.

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1974 - 19792

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End date: 1989Subject: search.filters.subject.Heavy-metal tolerant plants

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    Biogeochemical studies on some nickel accumulating plants from New Zealand and New Caledonian serpentine areas : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University
    (Massey University, 1974) Lee, Julian
    Serpentine areas in New Zealand and New Caledonia are described. A study was made of soil factors controlling the distribution of five species from a serpentine flora in the Dun Mountain area, South Island, New Zealand. Samples of soil were taken from sites of each of the species, and each sample was analysed for calcium, chromium, cobalt, copper, magnesium, manganese, nickel, potassium and zinc. On the basis of the species growing on them, the soil samples were divided into five groups: group 1, Pimelea suteri; group 2, Myosotis monroi; group 3, Lebe odora; group 4, Cassinia vauvilliersii; group 5, Leptospermum scoparium. Discriminant analysis was used to characterise each group of soils on the basis of chemical composition. The results showed that the two endemic plants (P. suteri and M. monroi) were much more commonly found in localities of highest magnesium concentration. These two species were strongly differentiated by the potassium and copper levels in their soils. No strong elemental discrimination was found among the non-endemic species. Correlation coefficients were calculated for the relationships between pairs of elements and highly-significant correlations (P 0.001) are reported. A nickel accumulating species from New Caledonia, Homalium kanaliense is compared with the New Zealand nickel accumulator, Pimelea suteri. The very high accumulation of nickel in the New Caledonian species, presents interesting questions in plant physiology. Purification of nickel complexes from an aqueous extract of B. kanaliense leaves was achieved and preliminary identification methods employed. None of the nickel was associated with amino acids and the present evidence suggested possible complexing of the nickel to simple carboxyllic sugars.
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    Ecological and phytochemical studies on nickel accumulating plants from the Pacific Basin region : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University
    (Massey University, 1979) Kersten, William J
    The distribution of species and genera contained in the floras of the Pacific Basin region is discussed. The outstanding feature of these floras is the high degree of specific endemism. A survey of the 53 species of Flacourtiaceae known in New Caledonia was successful in identifying a tital of 19 nickel hyperaccumulating species. The seven previously recorded in the Homalium genus were re-identified using fresh material and a further ten were located in the Xylosma genus with one in each of Casearia and Lasiochlamys. A similar survey of the Phyllanthus revealed a further ten hyperaccululating species out of the 51 studied. It was also possible to characterise and identify a number of species from their nickel and/or cobalt contents. This was particularly true for the taxonomically-difficult section Heteroglochidion. It appears that many nickel accululating plants are exclusive to ultrabasic substrates and as well as being able to tolerate high concentrations of the non-essential heavy metals they are also able to withstand extremely low levels of the essential elements. Pot trials showed that a strong relationship existed between soil and leaf nickel concentrations in Psychotria douarrei. Elemental concentrations were determined in several specimens of Rinorea bengalensis growing over a wide variety of substrates throughout the Pacific Basin region. It appears that soil conditions determine the extent to which an element is accumulated. Statistical considerations suggested a dependency on the organic constituents in the plant for the translocation of nickel. The nature of nickel complexes in several hyperaccumulating plants was investigated using gel filtration, ion exchange chromatroraphy, high pressure liquid chromatography and gas-liquid chromatography - mass spectrometry. Aquo, citrate and malate complexes of nickel were identified. Gel-filtration, electrophoretic and spectrophotometric comparisons with synthetic compounds suggested a 1:1 nickel/organic acid ratio exists in vivo. All species studied contained aquo and citrate complexes, but Psychotria douarrei and Phyllanthus serpentinus also have a large portion of their nickel bound in a malate complex. Possible factors determining the formation of a particular nickel complex are considered as is a possible pathway for the translocation of such a complex within the plant.