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    Aspects of growth control in kiwifruit and blackcurrant : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University
    (Massey University, 1979) Lawes, George Stephen
    This study emphasized the interplay of several types of growth regulator in the control of growth and development in the kiwifruit plant. Hence different parts of the plant are seen to contribute to this control, the plant appearing as a fully-integrated system with the shoots and roots interacting with each other. The gibberellins were active in the promotion of stem elongation, and it is considered stem growth is dependent on the photosynthate supply, and that this is mediated by the growth regulators. A leaf had a dominant effect on internode growth, and therefore shoot length, at a very early stage of its development - but the effect of an individual leaf was very localised. The plant roots were not clearly shown to be essential for breaking dormancy, bud burst, or early shoot growth. However it was found the roots could be supplying gibberellins as one of the factors required to maintain normal shoot growth. Cytokinins for early bud growth could have been supplied in the bleeding sap either from the roots or the stem tissue. Reservations are expressed about the need for high spring sap flows for plant growth. High sap flows may be a result of a combination of circumstances at the time, and not a necessary pre-requisite to growth. SADH and maleic hydrazide are effective shoot growth retardants, and may find commercial acceptance, except their apparent effect in enhancing post-harvest fruit respiration must receive further study. Bud dormancy was greatest before leaf fall, and dormancy was broken by about 700 hours below 7.2°C, although warm temperatures were just as effective in overcoming this dormant condition. Winter dormancy appeared to be basically the same type of condition as correlative inhibition, and it is suggested that each is, in large part a result of an inability to utilise cytokinins or other growth promoters. It is considered that the juvenile-like condition in blackcurrant is distinct from true juvenility,and the former did not appear to be the result of proximity to gibberellins from the roots. Further, it could not be shown for true juvenility that it was likely to be due to the production of inhibitory levels of gibberellin by the roots.
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    An analysis of polyphenolic blackcurrant (Ribes nigrum) extracts for the potential to modulate allergic airway inflammation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutritional Science at Massey University, Palmerston North, New Zealand
    (Massey University, 2009) Taylor, Janet Lynley
    The allergic disease of asthma is characterized by an infiltration of inflammatory cells to the lung, a process co-ordinated by T-helper (TH) cells. The TH2 cytokine Interleukin (IL)-4 promotes infiltration of eosinophils to sites of inflammation. Eosinophil-selective chemoattractant cytokines (eg. eotaxins) are synthesized by lung epithelial cells. Eotaxin-3 is expressed at high levels in the asthmatic lung, predominantly after IL-4 stimulation. Eotaxin-3 is therefore a marker of inappropriate airway inflammation. Polyphenolic (PP) compounds found in high concentrations in berries may have beneficial effects in inflammatory conditions. Plant and Food Research produced high-PP extracts of blackcurrant (BC) cultivars that were tested for inflammation modulating effects. Since high doses of PPs have been shown to cause cell death, we tested two BC cultivars at a range of concentrations in a cell viability (WST-1) assay. While no toxic effects were attributable to the BC extracts (1-50µg/ml), a dose-related trend in cell death was observed and therefore 10µg/ml was chosen for further experiments Ten BC cultivars were compared for efficacy by measuring eotaxin-3 production in IL-4 stimulated human lung epithelial (A549) cells in vitro. Cells were incubated with BC extracts (10µg/ml) and IL-4 (10ng/ml) for 24 hours. The supernatants were then quantified for eotaxin-3 levels by an enzyme-linked immunosorbent assay (ELISA). All ten BC extracts reduced eotaxin-3 levels after stimulation with IL-4, and six BC extracts were effective by statistically significant levels (P<0.05), (BC cultivars -01, -02, -03, -05, -09 & -10). Of those, BC extracts of four cultivars demonstrated a reduction of more than 65% from the IL-4 stimulated control. In addition, a positive trend in inflammation modulation vs. one anthocyanin (ACN) in the BC extracts was shown. This study has demonstrated the beneficial inflammation modulatory effects of polyphenolic BC extracts, which could be related to cyanidin 3-O-rutinoside content. These results may have therapeutic potential for asthma.