Sexual reproduction of interior spruce was investigated. In a preliminary study, seeds were produced from 50.5±20.0% of ovules in the most productive seed orchard trees. Seed production in most trees was far lower. Development between the time of pollination and early embryo formation was studied and reasons for low seed set are described. Low levels of pollination, as judged by dissection of ovules, was a problem in the seed orchard so the pollination mechanism was studied. The seed orchard is in a hot, dry location and there was a suspicion that pollination drops might not be produced under these conditions. Pollination drops were secreted very late by ovules as seed cones began to close at the end of the receptivity period. Micropylar arms withered and no longer functioned in pollen capture by the time pollination drops were secreted. Pollen move into inverted ovules by floating upwards within the pollination drop. Sacci, the 'wings' of conifer pollen, function as floatation devices in the pollination mechanism. Pollination drops are large and nearly fill the space that the micropyle occupies within the closed seed cone. Pollen adhering to the micropylar arms float within the pollination drop into the micropyle but, as well, pollen adhering to the cone axis near the micropylar arms are scavenged by the large drop. Rain may function in the pollination mechanism of interior spruce and an evolutionary scenario for the pollination drop mechanism is proposed. Picea orientalis has saccate pollen that sink into upright ovules. This is different from all other spruce so saccate morphology was investigated. TEM revealed that the exine layer of the sacci is porous when compared to interior spruce. Hydration of the pollen body forces air out of the sacci as observed by confocal microscopy. Ovule orientation and pollen floatation are described as correlated characters. An anatomical study was made of ovule development from pollination through fertilization and early embryo formation. Many of the observations confirm reports in the literature but examination of resin embedded specimens has allowed for a more detailed description of development. Many abnormalities which prevent fertilization were observed. Because prezygotic failure other than lack of pollen is not generally considered to be a constraint in conifer seed production, abnormal developments are described. Abnormal ventral canal cells and nucelli account for most of the observed prezygotic seed losses. Losses due to lack of pollen, and abnormal development were estimated at 15% each. Self-pollination results in low seed set in conifers so prezygotic development in self-pollinated ovules is described. Two types of prezygotic abnormality which prevent fertilization and that occur only after self-pollination were described and the possibility that some type of self-incompatibility mechanism might occur in conifers is discussed. Failure at prezygotic stages is common in interior spruce but it is generally only possible to observe these stages by doing careful study of the fertilization period. When seeds without developing embryos are examined after the time of fertilization it is usually impossible to tell if failure was pre-, or postzygotic. Seed losses in conifers are usually described to result from genetic load. The degree of prezygotic failure observed in this study suggests that conifers may not have as many embryonic lethal recessive alleles as estimated. Recommendations for increasing seed production in the seed orchard through effective use of supplemental pollen and for further studies of a botanical nature are made. / Graduate

Thesis (M.S.)--University of Wisconsin--Madison, 1980. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains vii, 69 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

Thesis (Ph. D.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains xii, 144 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references.

Rhododendron ponticum, introduced to the British Isles in 1763, has become a noxious invasive pest species, particularly in the west. Material of R. ponticum and its close allies in subsection Pontica were subjected to chloroplast DNA RFLP analysis. A preliminary phylogeny based on all cpDNA variation detected is presented. Suggestions regarding the interrelationships of these species are made, and a cpDNA-type of unknown taxonomic identity is tentatively identified. Chloroplast DNA differences were detected between native material of R. ponticum from Turkey, Spain and Portugal. Based on these differences, it was determined that approximately 90% of material naturalised in the British Isles originates from Spain and 10% from Portugal. These two types of material occur in roughly the same proportion throughout the British Isles. About 10% of naturalised accessions were found to contain an rDNA marker indicating nuclear introgression from R. catawbiense. Introgressed individuals are shown to be most common in the coldest region of the British Isles surveyed, i.e. E. Scotland, and it is suggested that introgression from R. catawbiense may confer increased frost tolerance to R. ponticum. The occurrence of the rDNA marker was not correlated with that of morphological markers indicating introgression. Correlations were found between morphological characteristics, which may result from introgression from cultivated species, such as R. maximum. Molecular evidence for the involvement of R. maximum in the ancestry of British R. ponticum was found in two accessions which resembled R. maximum. in certain morphological characteristics. It was established that another unidentified species was involved in the parentage of naturalised material. Five natural hybrid combinations amongst Turkish Rhododendron species were detected using morphological, cpDNA and nuclear rDNA markers. These were R. ponticum x R. ungernii, with introgression in both directions; R. ponticum x R. smirnovii; R. smirnovii x R. ungernii with introgression at least towards R. ungernii; R. smirnovii x R. caucasicum; and R. ponticum x R. caucasicum. The unusual characteristics of the last combination are discussed in some detail.

by Xu, Jing Huai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 119-126). / ABSTRACT --- p.i / ACKNOWLEDGMENTS --- p.ii / DEDICATION --- p.iii / TABLE OF CONTENTS --- p.iv / LIST OF ABBREVIATIONS --- p.viii / LIST OF FIGURES --- p.ix / LIST OF TABLES --- p.xii / Chapter 1. --- Introduction / Chapter 1.1. --- General Introduction --- p.1 / Chapter 1.2. --- Purpose of Study --- p.2 / Chapter 1.3. --- General Consideration and Objectives --- p.3 / Chapter 2. --- Literature Review / Chapter 2.1. --- Rhododendrons in Hong Kong --- p.9 / Chapter 2.2. --- History of Tissue Culture --- p.23 / Chapter 2.3. --- Tissue Culture of Rhododendron --- p.26 / Chapter 3. --- Materials and Methods / Chapter 3.1 --- General Protocol --- p.31 / Chapter 3.2. --- Plant Materials --- p.31 / Chapter 3.3. --- Culture Media / Chapter 3.3.1. --- Basal medium --- p.32 / Chapter 3.3.2. --- Sterilization --- p.32 / Chapter 3.4. --- Growth Condition --- p.33 / Chapter 3.5. --- Establishment of the Aseptic Culture / Chapter 3.5.1. --- Explants --- p.33 / Chapter 3.5.2. --- Pretreatment --- p.33 / Chapter 3.5.3. --- Disinfection --- p.33 / Chapter 3.5.4. --- Prevention of Browning --- p.34 / Chapter 3.6. --- Multiplication of the Culture / Chapter 3.6.1. --- General Operation --- p.35 / Chapter 3.6.2. --- Basal Medium --- p.35 / Chapter 3.6.3. --- Combination of Various Plant Hormones --- p.36 / Chapter 3.6.4. --- Addition of Vitamins --- p.36 / Chapter 3.6.5. --- Filter Paper as Supporting Material --- p.36 / Chapter 3.7. --- In Vitro Rooting / Chapter 3.7.1. --- General Operation --- p.37 / Chapter 3.7.2. --- Basal Medium --- p.37 / Chapter 3.7.3. --- Sucrose --- p.37 / Chapter 3.7.4. --- Auxin Concentration --- p.38 / Chapter 3.7.5. --- Activated Charcoal --- p.38 / Chapter 3.7.6. --- Effect of Ethylene on Rooting --- p.38 / Chapter 3.8. --- Acclimatization --- p.39 / Chapter 4. --- Results / Chapter 4.1. --- Establishment of the Aseptic Culture / Chapter 4.1.1. --- Optimization of the Disinfection Conditions --- p.45 / Chapter 4.1.2. --- Effect of Different Excised Plant Parts on Establishment of the Aseptic Culture --- p.47 / Chapter 4.2. --- Multiplication / Chapter 4.2.1. --- Effect of Basal Medium on Multiplication --- p.57 / Chapter 4.2.2. --- Combination of Plant Hormones --- p.57 / Chapter 4.2.3. --- Effect of Vitamins on Multiplication --- p.58 / Chapter 4.2.4. --- Using Filter Papers as Supporting Materials --- p.59 / Chapter 4.3. --- Rooting Studies / Chapter 4.3.1. --- Effect of Basal Medium Strength --- p.71 / Chapter 4.3.2. --- Effect of Sucrose Concentrations --- p.71 / Chapter 4.3.3. --- Effect of Auxins --- p.71 / Chapter 4.3.4. --- Effect of Activated Charcoal --- p.72 / Chapter 4.3.5. --- Effect of Ethylene --- p.72 / Chapter 4.4. --- Acclimatization / Chapter 4.4.1. --- Effect of Different Kinds of Supporting Materials for Transplanting --- p.90 / Chapter 4.4.2. --- Effect of Different pH on Growth of Explant after Transplanting --- p.90 / Chapter 4.4.3. --- Microcutting --- p.90 / Chapter 5. --- Discussions / Chapter 5.1. --- Factors Involved in Establishment of Aseptic Culture / Chapter 5.1.1. --- Quality of Explant --- p.97 / Chapter 5.1.2. --- The Importance of Sterility --- p.97 / Chapter 5.1.3. --- Prevention of Browning --- p.99 / Chapter 5.2. --- Multiplication of the Tissue / Chapter 5.2.1. --- Nutrient Media Factors --- p.101 / Chapter 5.2.2. --- Growth regulators --- p.101 / Chapter 5.2.3. --- Vitamins --- p.104 / Chapter 5.2.4. --- Supporting Material --- p.106 / Chapter 5.3. --- In Vitro Rooting / Chapter 5.3.1. --- Medium Strength --- p.107 / Chapter 5.3.2. --- Effect of Sucrose --- p.108 / Chapter 5.3.3. --- Effect of Auxins --- p.109 / Chapter 5.3.4. --- Effect of Activated Charcoal --- p.110 / Chapter 5.3.5. --- Ethylene --- p.111 / Chapter 5.4. --- Acclimatization --- p.115 / Chapter 6. --- Summary --- p.117 / Chapter 7. --- References --- p.119

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [92]-104).

Call number: LD2668 .T4 1979 A432 / Master of Science

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 69-76). Also available via the Internet.

No description available.