The principal objective of the study is the determination of geographic variation in white spruce in British Columbia. Since variation within this species in British Columbia is greatly influenced by hybridization with other spruce species, an attempt is made to demarcate zones of hybridization, and evaluate its effect on variation in white spruce. In a preliminary chapter the literature pertaining to principles and concepts of taxonomic and genecological investigation is critically examined in relation to infraspecific variation in tree species. The conclusions of this chapter constitute the assumptions of the investigation. A second chapter summaries the literature pertaining to the phylogeny and distribution of the spruce species of British Columbia, Photoperiodicity in forest trees is discussed in the third chapter. Following the chapters referred to above the study is divided into two parts, A and B. Part A is a study of the growth behaviour of 150 populations of spruce grown in a relatively uniform environment during a period of two years. The seed, which was collected throughout the spruce complex of British Columbia, was sown at the British Columbia Forest Service research nursery on Vancouver Island in the spring of 1965. Detailed measurements were made during the growing seasons of 1965 and 1966. In the laboratory seed samples of the same populations were X-rayed to determine embryo development and subsequently germinated at 25°C. Further seed samples were germinated at 15, 20, and 30°C. Part B is a study of geographic variation in mature populations of white spruce, and refers principally to a biometrical investigation of variation in cone scale morphology which was carried out on a mass collection of spruce cones collected in 157 areas throughout the range of spruce in British Columbia during the summers of 1963 and 1964. On the basis of the results obtained in parts A and B the following general conclusions are made: (i) In regard to the white-Engelmann spruce complex in British Columbia the environmental pressures which result in microevolution, i.e. infraspecific variation, differ only in degree rather than in kind from the environmental pressures which result in macroevolution, i.e. speciation. (ii) The faculty for normal development and survival of white spruce, and its related forms, is conditioned by the cessation of growth and initiation of dormancy. (iii) Time of initiation of dormancy in a population in any one region where the species occurs naturally is conditioned by its genetic constitution. (iv) The genetic constitution of a natural population is predominantly determined by the photothermal regime prevailing in that region. (v) In so far as there is a difference in the photothermal regime between any two regions the genetic constitution of the spruce populations occupying those regions will differ. (vi) One of the most important external manifestations of this difference is the time of cessation of growth and initiation of domancy. On the basis of these general conclusions, recommendations are made in regard to the silviculture of white spruce and its related forms in British Columbia, and also in regard to the field testing of the spruce populations referred to in part A of this study. / Forestry, Faculty of / Graduate

In the Creston valley in southeastern B.C., intermediate white clover is grown for seed and is a useful crop in farm field rotations. For several years seed yields have been declining, and despite good prices and markets, hectarage to white clover is declining. In 1976, work was initiated to determine some of the factors responsible for the decline in seed yield and hectarage. At the same time, an exploratory study of the genetic variation in the seed stocks of the valley was instituted in the hope that a Creston strain might be characterized or selected. In 1977, in the Creston valley, a series of replicated plots in six fields, representative of the edaphic, climatic and management regimes, were established to measure seed and forage yields and losses from multiple sources. At the University of B.C., four hundred individual plants representative of twenty sources, including some Creston sources, and encompassing substantial genetic diversity, were established from seed in replicated uniform nurseries. In an adjacent nursery one hundred and eighty Creston clones were established. Observation and measurement of a number of characters were taken on all plants several times during the growing season. Average clean seed yields on the Creston experimental plots ranged from 468-972 kgs. per hectare (418-868 lbs per acre). Farm yields of clean seed, by contrast, ranged from 262-491 kgs per hectare (240 to 450 lbs per acre). It was estimated that of the loss in seed threshed (dockage) , but not cleaned, 3-10% was insect damaged; loss attributable to farm harvesting procedures was estimated to reach 50%. Losses in the developing crop are difficult to assess quantitatively but appeared to be very serious. To offset these losses, in recent years, producers have been reducing the length of white clover ley and are now in most cases obtaining one seed crop only in the year after establishment; this practice, if carried on without counter selection, might result in a biennial habit. Three species of weevil appeared to be the most serious pests, viz. the clover root curculio (Sitona hispidula Fab.), and the clover seed weevil (Miccotrogus picirostris (F)) and the lesser clover leaf weevil (Hypera nigrirostris Fab.). The population peaks of the adults apparently occur at different times in the season. Currently only one aerial application of malathion is applied in June to control the clover seed weevil. Almost all roots examined bore signs of larval feeding, doubtless due to the clover root curculio; root nodules, abundant in spring, diminished rapidly as the season progressed. Measurements of nitrogen fixation, using the acetylene reduction technique and the Kjeldahl N-determination, were incomplete. Flower frequency and development, flower colour, leaf area, petiole length, leaf markings, plant height and weight, and prussic acid levels were some of the characters measured and observed on the individual plants, established in the U.B.C. nurseries from Creston and other sources. Not unexpectedly, the Creston stocks possessed a measure of distinction from most other stocks of intermediate white clover; nonetheless, there appeared to be ample variability in the Creston stocks within which to select strains to meet at least two needs of the region - viz. a) plants useful in the revegetation of ranges and of unstable soils, and b) plants well adapted to the arable long ley pastures of the humid and sub-humid areas. / Forestry, Faculty of / Graduate

Thesis (Ph. D.)--Virginia Polytechnic Institute, 1966. / Vita. Abstract. Includes bibliographical references (leaves 288-293). Also available via the Internet.

Thesis (M.S. in food science)--Washington State University, May 2009. / Title from PDF title page (viewed on July 28, 2009). "School of Food Science." Includes bibliographical references.

Thesis (Ph.D.)--University of Idaho, June 2006. / Major professor: Kenneth D. Cain. Includes bibliographical references. Also available online in PDF format.

Thesis (Ph. D.) -- University of Tennessee, Knoxville, 2006. / Title from title page screen (viewed on February 6, 2007). Thesis advisor: Timothy G. Rials. Vita. Includes bibliographical references.

Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 86-96). Also available on the World Wide Web.

In response to concern over the failure and poor growth of many interior and white spruce plantations in British Columbia the effect of storage duration and soil temperature on the photosynthetic ability of white spruce seedlings was explored. Seedlings of Picea glauca were dark freezer stored (-5°C) from 9.6 to 30.6 weeks, thawed and grown for 28 days in a growth chamber at three different soil temperatures (3,7,11°C). During this period gas exchange variables and chlorophyll fluorescence kinetics were followed. Seedlings stored for periods of 22 weeks or longer had significantly lower rates of photosynthesis dependent on the outplanting soil temperature. Stomatal conductance was initially low upon outplanting and showed a recovery period of 4-7 days duration. The level of stomatal conductance increased in seedlings after they were stored for 26.1 weeks or longer. Chlorophyll fluorescence measurements of seedlings stored from 22 to 30.6 weeks showed a recovery period in photosynthetic efficiency (Fy/Fp) related to changes in photosynthesis. A decrease in seedling Fy/Fp with increasing periods of storage was noted at day 5 after outplanting. A disproportionate increase in new root growth with the increasing soil temperatures, measured after the 28 day growth period, suggested a soil temperature threshold for root growth exists between the 7°C and ll°C. In contrast, the stomatal conductance and photosynthesis results suggest the seedling shoots were not directly affected by the cold soil temperatures. In general, the results suggest Picea glauca seedlings stored longer than 22 weeks in freezer conditions have reduced photosynthetic ability, root growth and overall vigor. Fluorescence and bud break data suggest the reduction was possibly due to freezing damage sustained in storage affecting photosynthetic electron transport through photoinhibition upon returning seedlings to the light. / Forestry, Faculty of / Graduate

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree Doctor of Philosophy. Johannesburg 2017 / The translocation of rhinoceroses is extremely stressful to the animal and this may strongly affect the success of translocation. The objectives of this study in white rhinoceroses were to (i) validate a non-invasive assay using faecal metabolites to assess the stress response in the white rhinoceros, (ii) to assess the stress response in the white rhinoceros associated with capture, handling, transportation and confinement, to be able to predict at capture which animals will adapt to confinement, and (iii) to investigate the use of the acute phase proteins (APP), serum amyloid A (SAA) and haptoglobin (Hp) as indicators of stress associated with capture and confinement. To achieve these objectives blood and faecal samples were collected from each rhinoceros at capture, and whenever possible, during confinement. To assess the hypothalamic-pituitary-adrenocortical axis (HPA) response of white rhinoceroses an ACTH challenge was performed and plasma cortisol and faecal glucocorticoid metabolites (FGM) were measured with a commercially available 125I RIA kit and a 125I corticosterone RIA kit, respectively. Gastrointestinal transit time was estimated with the use of an inert marker. Results showed a 4-to 8-fold increase in plasma cortisol within 15 to 20 minutes and a 3-fold increase in FGM concentration 60 to 90 hours later. Although this FGM measurement is non-invasive, relevant and robust, the time required to complete the extraction and assay could take several days. This measurement can be advantageous to monitor the stress of animals in confinement but has no application where animals are captured and immediately translocated. Measurement of plasma cortisol and FGM was also used to assess stress in rhinoceroses following transportation and in confinement. The results show that rhinoceroses have variable individual responses to capture and confinement and although there was evidence of behavioural habituation, HPA activity showed that there was no physiological habituation. We could not establish any predictor of success of habituation in the boma environment. The APP results showed that Hp is more likely to be an indicator of metabolic stress; rather than physical and psychological stress; while SAA responds rapidly to physical and psychological stress in the rhinoceros. It was also found that plasma cortisol was positively associated with SAA concentration when the animal is transferred to the boma, and that SAA may be a potential plasma biomarker to identify animals which could be at risk of failing to habituate to confinement. / MT 2018