ix, 210 leaves : ill. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Physiology, 1973

No description available.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Plant Physiology, 1973.

Thesis for B.S. in Agr. / Includes bibliographical references.

Ten different measurements or counts were made on peach leaf samples of 5 varieties in 6 locations in 3 years with the main objective being to test the possibility of identification of varieties in nursery trees. From the ten measurements, length of leaf blade, cm; width of leaf blade, expressed as percentage of length of leaf blade; base angle, measured at 1.5 cm from leaf base; maximum apex angle; and length of petiole, expressed as percentage of length of leaf blade, showed higher discriminative value than the other measurements under test. None of these measurements alone made it possible to distinguish between certain related varieties. Application of discriminant function analysis showed promise in identification of these varieties. Variation of the five characters which were used in construction of discriminant functions was found to be mainly in two dimensions and was expressed with two discriminant functions. The compound scores of two discriminant functions of the varieties could be simply plotted on two axes of a chart. Application of the discriminant functions is simple and consists in comparing the compound scores of an unknown sample to those of the average values of known varieties. The variety averages and corresponding compound scores of discriminant functions were calculated and used separately for three different growing regions of British Columbia. Large leaves from the middle portion of the central shoot of the one-year-old peach trees gave reliable samples. / Land and Food Systems, Faculty of / Graduate

Redhaven peaches treated with gibberellic acid (GA, 100 ppm) and ethephon (75 and 150 ppm) 21 and 46 days after full bloom were evaluated for enzymatic browning in the ripe fruit. Treated fruit had less browning than untreated fruit, and fruit treated 46 days after bloom had less browning than fruit treated 21 days after bloom. Fruit pH and fresh weight were affected by treatment, but o-diphenol content and polyphenoloxidase (PPO) activity were not. Forward stepwise multiple regression on browning showed that 81% of the variation in browning was explained by differences in treatment, treatment application date, o-diphenol content, PPO activity, and fresh weight. Twenty-one polyphenolic compounds from Redhaven peaches were separated by two-dimentional thin layer chromatography. Eight were oxidized by PPO, and were tentatively identified as four chlorogenic acid isomers, three leucoanthocyanidins, and catechin. No differences in qualitative distributions of phenolic compounds were observed in peaches receiving the different treatments. Polyacrylamide disc gel electrophoresis of peach PPO preparations showed the presence of up to eleven isozymes with activity toward catechol. The isozymes had different substrate specificities and were present in different amounts. PPO from peaches treated 21 days after bloom appeared to have a catechol reactive isozyme not present in untreated peaches or peaches treated 46 days after bloom. One PPO isozyme from peaches treated 46 days after bloom with 150 ppm ethephon appeared to have decreased substrate specificity toward pyrogallol. Crude PPO preparations from untreated fruit and fruit receiving the 46-day treatments oxidized o-dihydroxyphenolic compounds only. The relative activities of the PPO preparations with these compounds varied with treatment. The same PPO preparations exhibited two pH optima; pH 4.4 and 6.2 for untreated and GA treated peaches (46-day treatment), and pH 4.4 and 6.6 for peaches treated with ethephon (75 or 150 ppm, 46-day treatment). PPO from the treated peaches had a lower proportion of total activity at pH 4.4 than PPO from untreated peaches. The Michaelis constant for PPO from untreated peaches was 9.1 x 10⁻³M. / Land and Food Systems, Faculty of / Graduate

Thesis (Ph.D.) -- University of Adelaide, Dept. of Plant Physiology, Waite Agricultural Research Institute, 1966. / Typescript.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1950. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 87-88).

Thesis (Ph. D.)--University of Florida, 1972. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 94-103).

No description available.