Thesis (M.S.)--Oregon State University, 1973. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Clonal propagation of white spruce (Picea glauca (Moench) Voss) through somatic embryogenesis (SE) has important applications in tree improvement programs and will help the forest industry to achieve maximum sustainable yield. The level of induction of embryogenic tissue and the yield of mature embryos through SE has reached acceptable levels using current protocols. However, a large percentage of these embryos produce abnormal seedlings. This problem needs to be assessed and this was done in the work described in this thesis. Empirically derived, uncontrolled partial desiccation procedures are currently used to improve germinaton. No systematic study has previously been done to correlate the effects of controlled desiccation on germinant quality. My study looked at the effects of controlled partial and complete desiccation of white spruce somatic embryos at four stages of development on subsequent germinant quality. Both slow desiccation at 5°C and flash desiccation at ambient temperature were examined. The effect of temperature treatments as an alternate means of improving germinant quality and its effect on desiccation tolerance were also examined. Dried somatic embryos are likely to suffer imbibitional damage as they (unlike zygotic embryos) have no protective structures surrounding them to regulate water uptake during imbibition. Therefore, the effects of various rehydration methods were also examined. Large numbers of mature embryos were required for our desiccation experiments. Therefore, a method of squashing the embryogenic tissue into a polypropylene mesh was developed. This method allowed embryogenic tissue to be easily transferred to fresh medium and produced a flat mat of mature embryos that were more accessible for harvesting. The tolerance of the embryos to desiccation, and the level of desiccation required to improve germinant quality, increased as the embryos matured. The largest improvement in germinant quality was achieved by slowly desiccating 39-d embryos at 5°C for 7 days over a 0.48 M NaCl solution with a water potential of -2 MPa and rehydrating them at 100% RH at a temperature of 5°C. This treatment produced approximately 84% normal germinants. More severe desiccation caused increasing damage. A temperature treatment of 5 and 10°C also improved germinant quality, producing 70- 80% normal germinants. The 5°C treatment can be used as a short-term storage method. Germinant quality from untreated embryos increased with maturity until the embryos became fully mature by 51 d, then quality quickly decreased. Mature 51-d embryos were stored for 8 weeks at 5°C with no loss of germinant quality. A 5°C temperature treatment for 4-8 weeks significantly improved the tolerance of 39-51 d embryos to flash desiccation (embryos were dried in a laminar flow hood and lost all free cytoplasmic water within 15 minutes). This has important applications in the development of synthetic seed. All of the 8-week cold stored 51-d embryos survived flash desiccation and 58% of them produced normal germinants. The roots developed desiccation tolerance faster than the cotyledons+hypocotyls. Rehydration experiments showed that slowly and rapidly desiccated embryos responded differently to the method of rehydration. Slowly desiccated embryos suffered less imbibitional damage if they were indirectly rehydrated at 100% RH. Flash desiccated embryos suffered less damage if they were rehydrated directly on germination medium. This suggests that there is no one simple explanation for damage as a result of desiccation and imbibition. Reduction of 2,3,5-triphenyltetrazolium chloride (TTC) was an effective test for delineating damaged areas in rehydrated embryos, but actual germination tests were the only way of accurately determining germinant quality. The above treatments have significantly improved germinant quality. / Graduate

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 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

Thesis (M.S.)--University of Wisconsin--Stevens Point, 2009. / Submitted in partial fulfillment of the requirements of the degree Master of Science in Natural Resources (Forestry), College of Natural Resources. Includes bibliographical references (p. 43-50).

No description available.

No description available.

Thesis (Ph. D.)--University of Washington, 1981. / Vita. Bibliography: leaves [155]-165.

Root development in Picea glauca seedlings was studied anatomically during the first year after germination. The cyclic pattern of elongation of individual roots was established about three months after germination. With progressing development, root hairs gradually diminished and colonization of roots by mycorrhizal fungi increased. The development of primary tissues in long roots, relative to the distance from the root tip, appeared to be related to their rate of root elongation. In these roots, the development of Casparian bands in the endodermis often occurred several millimeters away from the root tip. In elongating short roots, endodermal cells attained their primary state only 2-4 cells away from the proximal part of the apical meristem. In non-elongating roots, the secondary-state endodermis was connected to the metacutis just above the apical meristem. The development of Casparian bands was always prior to the maturation of the first xylem elements. The endodermis did not develop past the secondary state. Through the presence of passage cells, it remained functional until its disruption by secondary growth. Low frequency of plasmodesmata in the endodermis indicated that the plasma membrane - cell wall - plasma membrane type of transport was the main means of molecule exchange between the cortex and the stele in white spruce roots. Undifferentiated tissues of the root near the apical meristem were almost impermeable to fluorescent dye tracers Sulforhodamine G and fluorescein diacetate. The metacutis and the endodermis at the primary and secondary state were impermeable to the apoplastic tracer Sulforhodamine G. Roots and root systems were structurally and physiologically affected by cultural treatments such as pruning and fertilizer application. Roots of seedlings grown at low nitrogen (N) supply were thin and their tracheids were narrow. Excess N did not significantly increase root diameter and tracheid dimensions, compared to the optimum supply. Dimensions of bordered pits were not significantly affected by the N level. The secondary development in roots advanced basipetally but exceptions were found indicating that cambial growth of roots could vary along the root regardless of the position relative to the root tip. Seedlings with different root systems modified by nursery culture exhibited different pattems of root growth after planting. Root elongation and root surface area increases immediately after planting were greater in container-grown than in mechanically box-pruned seedlings but this was unrelated to the longer-term performance of these seedlings. The initially low hydraulic conductance of root systems in box-pruned seedlings increased significantly 6-8 weeks after planting while it remained unchanged or declined in container-grown seedlings. Root pressure, comparable to that reported for angiosperm seedlings, was found in white spruce seedlings during the first few weeks after planting. This is contrary to the general notion that conifers do not develop notable root pressure. The initiation and elongation of roots in unfertilized organic compartments was poor compared to root growth in unfertilized mineral compartments, especially in mechanically pruned seedlings whose roots proliferated in the latter compartments. The growth of roots in the organic substrates was enhanced by the addition of slow-release fertilizer to that substrate. The growth response of roots to slow-release fertilizer added to the mineral substrate was restricted to that compartment but root growth in both soil compartments was affected by the addition of slow-release fertilizer to the organic substrate. Root development in different types of planting stock was differently affected by the soil substrate type and the addition of the slow release fertilizer. / Graduate

No description available.