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Dissertations / Theses on the topic 'Orchids'

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Published: 4 June 2021
Last updated: 30 July 2024

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1

Hughes, Oliver Thomas Wesley. "Orchid-mycorrhiza relationships : propagation of terrestrial and epiphytic orchids from seed." Thesis, Manchester Metropolitan University, 2018. http://e-space.mmu.ac.uk/621969/.

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Many orchids are rare and endangered due to habitat loss, degradation and human interference. This thesis aims to improve our understanding of orchid-mycorrhiza relationships and optimise methods for successful in vitro germination and development of terrestrial and epiphytic orchids. The research undertaken advances our understanding of orchids and has applications for conservation and horticulture. Fungal specificity plays a key role in orchid distribution and the colonisation of habitats. This was investigated in the Australian terrestrial orchid, Microtis media R. Br. in Chapter 2. Experiments demonstrated low fungal specificity in germination in vitro, although later development was more specific, with one fungus inducing protocorm development through to adult plants. Fungal compatibility was tested in several Eurasian terrestrial orchids in Chapter 3. Varying degrees of specificity were observed, with Anacamptis morio (L.) R.M.Bateman, Pridgeon & M.W.Chase and Dactylorhiza incarnata (L.) Soό displaying low fungal specificity whereas Serapias spp. were more specific. Orchids are commonly propagated without fungi using asymbiotic media. Asymbiotic and symbiotic methods were compared in two Eurasian terrestrial orchids in Chapter 4. In both cases, symbiotic methods resulted in higher germination and development. In Anacamptis laxiflora (Lam.) R. M. Bateman, Pridgeon & M. W. Chase, successful seedling establishment ex vitro was only achieved with symbiotic seedlings. Following this study, the effect of substrate rugosity and complexity on germination in asymbiotic and symbiotic culture of two Eurasian terrestrial orchids was investigated in Chapter 5. Substrate rugosity had a positive effect on germination and development in symbiotic cultures of A. morio and both asymbiotic and symbiotic cultures of Dactylorhiza purpurella (T.Stephenson & T.A.Stephenson) Soó. The subtribe Pleurothallidinae is one of the largest in the Orchidaceae and little is known about their propagation requirements. A number species from different genera within this group were tested with different asymbiotic media and fungi isolated from plants in an ex situ collection in Chapter 6. Germination was highest with two fungal strains but development of plantlets only occurred on asymbiotic media. Ex situ study and propagation of myco-heterotrophic orchids poses some difficulties. A novel method is presented, using microcosms for the initiation of tripartite symbioses with tree seedlings, fungi and orchids in Chapter 7. Associations between tree seedlings, fungi and orchid seed were observed. Germination was not achieved with seed of Neottia nidus-avis (L.) Rich. The method provides a basis for further development with applications in a range of ecological studies.
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2

Yam, Tim-wing. "Conservation, ecology and propagation of the wild orchids of Hong Kong /." [Hong Kong : University of Hong Kong], 1988. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1243873X.

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3

Tsui, Yuk-chun Prisca. "Conservation and propagation of wild orchids in Hong Kong /." [Hong Kong : University of Hong Kong], 1992. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13226290.

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4

Shan, Xuechan. "Fungal associations and aspects of seed biology of some orchids of Hong Kong /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20566670.

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5

Liu, Bing. "Germination studies in terrestrial orchids." Thesis, University of Leeds, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303461.

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6

Yuh, Seon Hee. "Cloning genes differentially expressed in freezing tolerant orchids." Virtual Press, 1996. http://liblink.bsu.edu/uhtbin/catkey/1020165.

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Genes responsible for differences in gene regulation and expression in normal cells and freezing tolerant cells were identified using two related wintergreen orchid species, Aplectrum hyemale and Tipularia discolor. Changes in gene expression observed in field-collected tissues obtained from different seasons were compared as were changes observed in plants subjected to cold shock in a laboratory environmental chamber. In order to clone these differentially expressed genes which may confer photosynthesis cold tolerance, the recently developed technique, mRNA differential display was employed. Using this process, mRNA was isolated from the tissue and reverse transcribed to cDNAs, which were amplified using specific anchored 3' primers and various random 5' primers. The 50-100 bands resulting from specific primers were compared on denaturing polyacrylamide gels. Bands differently expressed were excised from the gel and purified. In the future, if partial sequence analysis indicates they may code important regulatory proteins, they will be used as probes to obtain full-length genes from a cDNA library for further characterization. This study provides an opportunity not only to obtain important regulatory genes in plants, but also to understand more about temperature regulated gene expression in orchids.
Department of Biology
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7

Barkman, Todd James. "Evolution of Dendrochilum subgenus Platyclinis section Eurybrachium investigated in a phylogenetic context /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

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8

Hart, Phoebe. "Orchids : intersex and identity in documentary." Thesis, Queensland University of Technology, 2009. https://eprints.qut.edu.au/29712/25/Phoebe_Hart_Thesis_redacted.pdf.

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Orchids: Intersex and Identity in Documentary explores the creative practice challenges of working with bodies with intersex in the long-form auto/biographical documentary Orchids. Just as creative practice research challenges the dominant hegemony of quantitative and qualitative research, so does my creative work position itself as a nuanced piece, pushing the boundaries of traditional cultural studies theories, documentary film practice and creative practice method, through its distinctive distillation and celebration of a new form of discursive rupturing, the intersex voice.
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9

Hart, Phoebe. "Orchids : intersex and identity in documentary." Queensland University of Technology, 2009. http://eprints.qut.edu.au/29712/.

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Orchids: Intersex and Identity in Documentary explores the creative practice challenges of working with bodies with intersex in the long-form auto/biographical documentary Orchids. Just as creative practice research challenges the dominant hegemony of quantitative and qualitative research, so does my creative work position itself as a nuanced piece, pushing the boundaries of traditional cultural studies theories, documentary film practice and creative practice method, through its distinctive distillation and celebration of a new form of discursive rupturing, the intersex voice.
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10

Wong, Kwong-chiu Alfred. "Conservation genetics of Hong Kong wild orchids /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2035793X.

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11

Kim, Bong-Suk. "Cloning of genes encoding desirable characteristics of dendrobium gatton 'sunray'." Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/941349.

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Currently the breeding of desirable traits in orchid flowers is a lengthy and unpredictable process. A shortened breeding time and a more direct method of introducing specific genetic characteristics could be achieved if more information were available on the specific genes responsible for flower characteristics. In order to identify some of these genes, the genetic relationships between a hybrid, Dendrobium Gatton 'Sunray', and the parent species bred to produce it, D. chrysotoxum Lindley and D. pu/che//um Lindley were examined.Ball State UniversityMuncie, IN 47306These results were supported by Restriction Fragment Length Polymorphisms (RFLPs) observed following amplification of the Internal Transcribed Spacer (ITS) regions of the rDNAs.In order to clone genes responsible for specific flower characteristics, mRNA differential display was performed using total RNA isolated from the leaves, immature flowers, and mature flowers of the hybrid orchid and its two parents. Bands unique to D. Gatton 'Sunray' flower tissue, which were common to the hybrid and a single parent, were excised from a denaturing acrylamide gel. Four of the bands, which represented expressed genes determining inherited flower characteristics, were re-amplified, cloned, and three were sequenced. Partial sequence information obtained for two of the clones was used to search the GenBank database for homologous genes. One of the clones had sequence homology to plant 26S ribosomal genes and the other clone was homologous to sequences encoding regulatory proteins active during development (for example, the human retinoblastoma susceptibility gene or the Caenorhabditis e/egans cosmid R06F6 containing a serine/threonine protein kinase gene).
Department of Biology
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12

Petersen, Kellie. "Hybridizers and the Hybridized: Orchid Growing as Hybrid "Nature?"." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7350.

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Orchid growing is a hobby that includes not only acquiring and caring for orchids, but also learning about the diverse care requirements of various orchids, attending meetings of orchid groups, having one’s orchids evaluated by American Orchid Society judges or being a judge, or even creating hybrids. In this way, orchid hobbyists compose a distinctive subculture (Hansen 2000). Yet the activity of orchid growing also forms a nexus between the non-human and the human, two categories that are often constructed as an opposing binary. This thesis focuses on how orchid growing represents both the embedded, institutionalized characteristic of the binary between the non-human and the human and how this binary is actively deconstructed; that is, orchid growers often reinforce this binary through positioning their orchids as a part of “nature” and also blur it by participating in the activity of orchid growing. Through observations of monthly meetings of two local orchid groups and affiliated events and walking tours of individual participants’ orchid growing spaces and semi-structured interviews with them, I show how orchid growing represents such a “hybrid” form of nature (Whatmore 2002). Specifically, the ways in which orchid growers appreciate the novelty of their orchids, care for them, and establish authenticity in orchid growing demonstrates the nuanced ways orchid growing forms a relationship with “nature.”
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13

Wong, Kwong-chiu Alfred, and 黃廣潮. "Conservation genetics of Hong Kong wild orchids." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31221920.

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14

Marchione, Wesley A. "Pathogen resistance genes and proteins in orchids." Virtual Press, 2003. http://liblink.bsu.edu/uhtbin/catkey/1260625.

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To study resistance (R) genes that are expressed when Sophrolaeliacattleya Ginny Champion 'Riverbend' orchid tissue was infected with the tobacco mosaic virus (TMV0), a subtraction library of cDNA clones was previously constructed using mRNA isolated before and after infection (Shuck, unpublished). From 200 clones collected, 5 clones were randomly selected, DNA was isolated, and the cDNA insert was sequenced. These sequences were imported into BLAST to search for homology to other R genes. This search revealed clone 4A to have an 84% homology to a 54 nucleotide region from the Arabidopsis thaliana oligouridylate binding protein which is highly expressed and known to bind RNA Polymerase III transcripts and adenovirus associated RNAs. Further bioinformatics analysis was performed utilizing databases and analysis packages available on the Internet, software such as Vector NTI (Informax, Bethesda, MD), and manual searches. However, no additional domains or motifs indicative of pathogen resistance genes were located in any of the 5 clones. Subsequently, total proteins expressed at various time points following infection were examined on denaturing 5-20% gradient polyacrylamide gels stained with the ProteoSilver Plus TM silver stain kit (Sigma, St. Louis, MO) in order to examine the timing and duration of expression of proteins involved in TMV-O resistance. One protein of-18 kDa was highly expressed at 4 hr after infection that was not seen in the negative control. By 8 hr the band was no longer expressed, it was expressed again from 30 - 48 hr, but was not seen again in later time points. Finally, total mRNA isolated from pooled time points and subjected to in vitro translation indicated a reduction in translation products after infection, providing evidence of posttranscriptional gene silencing (PTGS) following TMV-O infection.
Department of Biology
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15

Darkwa, Alfred Anthony. "Growth and biochemistry of hardy European orchids." Thesis, University of Sussex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495011.

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16

Neiland, Mary Ruth Miller. "Reproductive ecology of British and Mediterranean orchids." Thesis, University of Aberdeen, 1994. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU072992.

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Factors contributing to the natural reproductive performance of flowers, plants and populations of British and Mediterranean Orchidaceae are considered. Reproductive success is found to be pollinator limited, with most European orchids failing to achieve their maximum potential within the season, particularly nectarless species. There is a consistent discrepancy in gender function, with many more pollinia being removed than returned, because of pollinator foraging behaviour. Patterns of insect visitation to orchids are influenced by inflorescence and labellum characters, such as floral spurs. Spurs vary in size and shape between species, and many are nectarless. Trichomes are often present on the inner surface, and may prolong insect visits. The principal orchid pollinators are all members of the Hymenoptera, Lepioptera and Diptera, which normally visit other plants for food. Co-occurring species can act in a facilitative way to maintain a band of local pollinator, and pollination of all species examined is found to be significantly associated with the presence of 1 or 2 key foreign species or a guild of such plants. Under conditions of infrequent pollination, various features of the European Orchidaceae act to maximise their reproductive success when pollination does occur. The flowers are found to be long-lived and remain receptive to additional pollinations which may lead to increased seed quantity and diversity. Pollen maintains viability for several week which prolongs the opportunity of insect transported pollinia to effect pollination. Break up of pollinia into smaller dispersal units increases the likelihood of widespread dispersal and reduces pollen wastage. Even the smallest pollen load is found to stimulate embryogenesis, but more seeds are set with larger loads. PL:O ratios of 2-3:1 are most commonly found, which should result in both maximal seed set and increased quality of the offspring. Furthermore, seed output is significantly associated with fruit set and average levels of capsule formation are consistently higher in nectariferous orchids than in nectarless ones. Most rare British orchids are nectarless, and are particularly vulnerable to environmental alterations which influence the floral composition of their habitat, and density and distribution of supporting species.
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17

Toscano, de Brito Antonio Luiz Viera. "Systematic studies in the subtribe Ornithocephalinae (Orchidaceae)." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386911.

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18

Khayota, Beatrice N. "Systematics of the genus Ansellia Lindl. (Orchidaceae)." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283021.

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19

Ryan, Angela. "A phylogenetic assessment of Lycaste and Anguloa (Orchidaceae)." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252249.

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20

Goldman, Douglas H. "Systematics of Calopogon and the tribe Arethuseae (Orchidaceae) /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.

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21

Qamaruz-Zaman, Faridah. "Conservation genetics of rare and endangered British orchids." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621726.

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22

Tamang, Ranju. "Micropropagation of some orchids of darjeeling and sikkim himalayas." Thesis, University of North Bengal, 2011. http://hdl.handle.net/123456789/1437.

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23

Bichsel, Rebecca Gayle. "Determining the nutritional requirements for optimizing flowering of the nobile dendrobium as a potted orchid." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1116.

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24

Chan, Man-chung. "Genetic diversity and relationships of spiranthes sinensis, S. spiralis, and S. hongkongensis (orchidaceae) as revealed by RAPD and cpDNA markers /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19324200.

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25

Kanjilal, Biswajit. "Biotechnological approach towards conservation of certain endangered orchids of North Bengal." Thesis, University of North Bengal, 1999. http://hdl.handle.net/123456789/928.

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26

Bhaumick, Debangshu. "Developmental biology and tissue culture studies in some commercially important orchids." Thesis, University of North Bengal, 1991. http://hdl.handle.net/123456789/898.

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27

Saxon, Herbert. "The molecular biology of orchids : transformation by Agrobacterium Tumefaciens and DNA fingerprinting." Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/941575.

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The work reported here was done at the Wheeler Orchid Collection and Species Bank and the Department of Biology at Ball State University. We have developed a research teaching program with two applied research goals: genetically transforming and DNA fingerprinting orchid tissue. As part of their molecular biology education, students have investigated the genetic transformation of orchids for mitigating viral symptoms and the identification of unknown orchids by DNA fingerprinting. In a second application of the technology, DNA fingerprinting has been used to determine evolutionary relationships and to quantify genetic diversity among orchids.This dissertation details the background and need for this project and the research that was done to start it. As the early work has, developed and students have added their contributions, the data have developed into two papers formatted for submission to scientific journals. They are included as results.The first is a project designed to insert exognenous DNA into orchid tissue. The soil microbe Agrobacterium tumefaciens causes crown-gall tumors to develop in its plant hosts by inserting DNA into their cells which then controls the biosynthesis of development-controlling hormones. A. tumefaciens which has been disarmed has been routinely used to bioengineer dicotyledonous plants but its use has been rare on monocotyledons. In this paper, we report that A. tumefaciens transformed embryonic orchid tissue and caused alteration in its normal developmental course.The second paper details the DNA fingerprinting of tissue from Aplectrum hymale, a terrestrial orchid native to this climate. Three populations of A. hymale have been sampled and DNA extracted from the tissue samples. RAPD primers were used to prime PCR amplifications of random sequences of the DNA and the amplified DNA was visualized by gel electrophoresis. Loci of the resulting bands were treated as potentially multiallelic gene loci and heterozygosity between and within subpopulations was calculated. We report that the three populations could be partially differentiated by this procedure and that the two populations located nearest to each other yielded the least between -ubpopulation heterozygosity. We report very high levels of genetic diversity between individuals within small subpopulations in spite of the fact that these subpopulations are considered to be primarily clonal in reproductive nature.
Department of Biology
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28

Tsui, Yuk-chun Prisca, and 徐玉珍. "Conservation and propagation of wild orchids in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B31210570.

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29

Powell, Martyn P. "Evolutionary ecology of neotropical orchids, with emphasis on Oncidiinae." Thesis, University of Reading, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494102.

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This thesis investigates speciation in Neotropical orchids, with a focus on the subtribe Oncidiinae, which has undergone a dramatic radiation in the Neotropics. A near-complete species-level phylogeny of the Tolumnia clade (a subset of the Oncidiinae), comprising 47 of the 51 currently recognised species, based on multiple plastid (trnH-psbA, trnL-F, rps16) and nuclear DNA regions (ITS and ETS) provides a well resolved and robust framework from which to address questions about the evolutionary history of this group. It also permits the clarification of the taxonomic status of certain anomalous taxa, including the genus Amparoa which is found to be embedded within Rhynchostele. Significant levels of rate heterogeneity are observed between the lineages of this phylogenetic tree, and potential causes, both physiological and ecological, of these are examined, although no single causal factor is identified.
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30

Roberts, David Lesford. "Reproductive biology and conservation of the orchids of Mauritius." Thesis, Aberystwyth University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367505.

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31

Chesselet, Pascale Claude Marcelle Henriette. "Systematic implications of leaf anatomy and palynology in the Disinae and Coryciinae (Orchidaceae)." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/18698.

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Pollen morphology of 8 species (TEM), 86 species (SEM), and leaf anatomy of 62 species (LM), were surveyed in the Oisinae, Coryclinae and, as outgroup taxa, the Orchideae and Satyriinae. Characters extracted from observations made of leaf anatomy and pollen were analysed using cladistic methods, and assessed in relation to the present phylogeny of the group. Leaf anatomy data gave little phylogenetic information. Sclerification associated with vascular bundles was systematically useful. Pollen data served to resolve taxa at the subtribal level. Both data sets provided evidence of relationship for taxonomically problematic taxa. The Coryciinae are palynologically defined by a suite of synapomorphies, including a secondarily tectate exine structure, fasciculate massulae, and elongated tetrads with linear microspore configuration. Bibliography: pages 107-123.
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32

Yam, Tim-wing, and 任添榮. "Conservation, ecology and propagation of the wild orchids of HongKong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B31231731.

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33

Ackerman, Rodney Rex. "The effects of complex additives and growth regulators on the growth and clonal propagation of Phalaenopsis orchids." Virtual Press, 1988. http://liblink.bsu.edu/uhtbin/catkey/546145.

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The goal of this study was two fold, the first was to determine the effect of different basal medium formulationsand medium supplements (complex additives and growth hormones) on the development and growth rate of Phalaenopsis orchids, while the second goal was to find or develop an efficent method for the clonal propagation of Phalaenopsis orchids.MethodsThe first part of this study was further subdivided in to several phases; the first of these involved a comparative study of the germination of Phalaenopsis ovules on six different basal medium formulations and seven different sets of medium supplements. The second phase involved a comparative study of the development of Phalaenopsis protocorms on six different basal medium formulations and ninteen different sets of medium supplements. The third phase involved a comparative study of the growth of Phalaenopsis seedlings on six different basal medium formulations and twelve sets of medium supplements. The forth and final phase involved a comparative study of the development and growth of Phalaenopsis protocorms and seedlings on media containing varing concentrations and combinations of auxins and cytokinins. The second part of this study involved a comparative study designed-to determine the suitability of several sizes of axillary buds and plantlets for the clonal propagation of Phalaenopsis orchids and the modification of several procedures in an attempt to determine suitable explant material and procedures for the commercial clonal propagation of Phalaenopsis orchids.Results and DiscussionResults of this study indicated that of the basal medium formulations and medium supplements tested Modified Heller's salt base medium and to a lesser extent Modified Vacin and Went salt base medium supplemented with vitamin formulation 1 and Bactopeptone yielded the highest percent germination and development up to the seedling stage. At the seedling stage the growth rate of seedlings grown on media supplemented with banana homogenate nearly doubled the growth rate of the seedlings grown on all of the other medium supplementstested.Results of the second part of this study indicated that by modifying the procedures of Bouriquet, Broly, and Legrand (1982) the proliferation rate (shoots per plantlet) could be increased by a factor of two to eight. This can be translated into an increase from two to five shoots per plantlet per six weeks to an increase of eight shoots per plantlet per six weeks with a minimal mortality rate. With further modification of the procedure of Bouriquet, Broly, and Legrand (1982), other results indicated that it may be possible to increase to forty the number of shoots per plantlet produced per six week period.
Department of Biology
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34

Stewart, Scott L. "Integrated conservation of Florida Orchidaceae in the genera Habenaria and Spiranthes : model orchid conservation systems for the Americas /." View online, 2007. http://etd.fcla.edu/UF/UFE0021367/stewart_s.pdf.

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35

Devey, Dion Stuart. "MARC RecordSystematics and conservation of Mediterranean insect-mimicking orchids (Ophrys)." Thesis, University of Reading, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494444.

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Historically, Ophrys morphological taxonomy and species delimitation have been controversial, with treatments inferring from 16 species plus 34 subspecies to as many as 252 species forming 32 complexes. Highly variable, yet possibly convergent, morphologies and paucity of sequence variation have hindered production of a robust phylogenetic framework. This project generated phylogenies and ordinations from nuclear and plastid DNA sequencing, amplified fragment length polymorphism (AFLP) and morphometric data, with the ultimate aims of producing a robust framework as a basis for more rigorous species delimitation and conservation recommendations for the genus. The project also elucidates genetic and morphological relationships within Ophrys section Ophrys, and within the 0. fuciflora and 0. sphegodes aggregates, and assesses the congruence between these contrasting datasets.
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36

Nam, Kam-shing, and 藍金成. "Conservation of Hong Kong wild orchids by leaf tip culture." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31212591.

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37

Newman, Belinda. "Orchids as Indicators of Ecosystem Health in Urban Bushland Fragments." Thesis, Newman, Belinda (2009) Orchids as Indicators of Ecosystem Health in Urban Bushland Fragments. PhD thesis, Murdoch University, 2009. https://researchrepository.murdoch.edu.au/id/eprint/2374/.

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In this thesis I investigate the utility of orchids as indicators of ecosystem health. The study areas were urban bushland fragments on the Swan Coastal Plain, a global biodiversity hotspot. The study focuses on the abundance, reproductive success, mycorrhizal abundance and seedling biomass accumulation of a suite of native terrestrial orchids common to Perth’s urban bushland fragments. A critical factor in exploring the ecological responses of these orchids to site condition and their application as indicators of ecosystem health is the assessment of the ecosystem health of each of the study sites. I studied the vegetation condition gradient across eleven urban bushland fragments using three known ecosystem health assessment methods. Correlations were found between the perimeter to area ratio, native vegetation cover, weed cover and canopy cover in relation to site condition gradients. Floristic complexity at sites was found to mask relationships with environmental variables that were apparent following classification into plant functional groups. Of the plant functional traits only facultative sprouter, sub-shrub, barochory and perennial trait frequencies correlated with the vegetation condition gradient, all traits showing a decline with decreasing vegetation condition. Multivariate analysis of orchid abundances and environmental parameters revealed three orchid species that could potentially be used as indicators of ecosystem health. Diuris magnifica and Microtis media correlated strongly with poor condition sites. Pterostylis sanguinea correlated strongly with very good condition sites. However, environmental parameters, floristic composition and plant functional groups provided weak correlation to orchid species presence and abundance. Reproductive response, mycorrhizal abundance and biomass accumulation across the vegetation condition gradient were then measured to determine the extent to which orchids can be used as indicators of ecosystem health. The effects of site condition on fruit set success were not found to be significant for any of the orchid species in this study. Widespread pollen limitation across sites revealed that fruiting success was likely to be too insensitive a measure for examining ecosystem health. Mycorrhizal distribution across the cline of condition was found to be patchy within fragments and revealed unoccupied niches capable of supporting orchid germination. Further evidence of the use of Microtis media as an indicator of poor condition sites was found in an increased abundance of the associated mycorrhizal symbiont. The abundance of mycorrhizal symbionts for Caladenia arenicola and Elythranthera brunonis at sites of very good condition indicated their potential use as indicators. An inverse relationship was found to exist between biomass allocation to leaf or tuber in sites of good and poor condition. In sites of poor condition, Diuris magnifica and Caladenia arenicola increased allocation of biomass to shoots presumably in order to obtain photosynthates. In sites of very good condition these two species increased their allocation of biomass to the tuber. Initial findings suggest biomass allocation in Caladenia arenicola and Diuris magnifica may be a useful tool in measuring ecosystem health. The lack of currently undisturbed urban remnants and a poor historical record of past disturbance events in the study sites make understanding the role of past disturbances on the current condition gradient difficult. The results of this study suggest that orchid presence and abundance, orchid growth and orchid symbionts can be used as indicators of ecosystem health, although work needs to be undertaken to refine the understanding of their response to specific disturbances. This study provides a baseline for investigating the utility of orchids as indicators of ecosystem health in highly fragmented systems.
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Oscar, Alejandro Perez Escobar [Verfasser], and Marc [Akademischer Betreuer] Gottschling. "Molecular phylogenetics, evolution of sexual systems and historical biogeography of Darwin's favourite orchids (Catasetinae) and Swan orchids (Cycnoches Lindl.) / Perez Escobar Oscar Alejandro. Betreuer: Marc Gottschling." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1110749163/34.

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Hutchinson, Chad M. "Agrobacterium tumefaciens mediated transformation of orchid tissue with the sense and antisense coat protein genes from the odontoglossum ringspot virus." Virtual Press, 1992. http://liblink.bsu.edu/uhtbin/catkey/834608.

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This research was an attempt to use a dicot transformation vector to transform a monocot. The initial purpose of this thesis was to transform orchids with the sense and antisense coat protein genes from the Odontoglossum ringspot virus (ORSV) in an effort to mitigate viral symptoms in transgenic plants using the transformation vector, Agrobacterium tumefaciens. However, it soon became apparent that much time would be needed to develop a transformation protocol. The transformation vectors used included the Agrobacterium tumefaciens disarmed strain LBA4404 with the binary plasmid pB1121, the disarmed strain At699 with the binary plasmid pCNL65, and the wild-type strain Chry5. The marker gene on the binary plasmids of both disarmed strains was p-glucuronidase (GUS).Several transformation protocols were used in an effort to determine if this transformation system would work on orchids. Transformation was not achieved even though a number of experimental conditions were varied. These included using two different types of orchid tissue, callus and protocorms; using two different species of orchids, Cattleya Chocolate Drop x Cattleytonia Kieth Roth and Cymbidium maudidum; varying the time the plant tissue was exposed to the bacteria from 1 hour to 96 hours; performing experiments with and without the wound signal molecule acetosyringone; and exposing the tissue to the virulent strains of A. tumefaciens mentioned previously.This research also developed GUS assay conditions necessary to decrease the number of false positives due to bacterial contamination. These conditions included chloramphenicol in the GUS assay buffer.
Department of Biology
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Quiroga, Fernandez Ana Isabel, and Yunfeng Wang. "Female Entrepreneurs - Orchids in the Forest : Conditions for female start-ups." Thesis, Linnéuniversitetet, Ekonomihögskolan, ELNU, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-12435.

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The last century has witnessed blooming achievements of females as rising workforce in modern society. With their active participation in business world recently, female entrepreneurship research has caught extensive attention globally, not only from academic field, but also from market entities, policy makers, social activists, as well as broad masses, concerning the social and economic contribution of female-started entreprises. Current studies within this topic concentrate on two issues: the difference between male and female entrepreneurs; demographic research for certain countries, regions, or industries. Following a qualitative research approach, this thesis applies implementations of actors view and grounded theory. With the purpose to create in-depth business knowledge, a well-structured empirical exploration is conducted mainly through theoretical sensibility acquisition, secondary data collection and face-to-face dialogues focusing on the issue of conditions for female entrepreneurs to start up and to develop a business.The researchers share their comprehensive (from both micro and macro perspective) understanding about this subject: There is no such a formula of necessary conditions existing. Female entrepreneurs need to define them according to the type of the ventures they establish and the demand for their projected growth, pursue them by taking actions instead of waiting for all conditions to be ready. The forthcoming female economy brings millions of opportunities that favor female entrepreneurs to start up enterprises, despite the current situation where they have not received effective supports that they deserve. In the end, the researchers create a new term „femesh‟ to conclude their findings and their anticipation for the future blossom of female entrepreneurs. Especially, the academic research process is described as an exploration adventure for searching orchids in the forest, together with the romantic writing style of the authors, bringing enjoyable readability without losing its preciseness, accuracy and logic as an academic research.
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Collins, Margaret Thora. "Factors affecting the recovery of orchids in a post-mining landscape." University of Western Australia. School of Earth and Geographical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0022.

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[Truncated abstract] Currently, Alcoa World Alumina Australia (Alcoa) mines and undertakes procedures to rehabilitate approximately 550 ha of jarrah forest each year at two open-cut bauxite mines in South-West Western Australia. Alcoa aims to establish a self-sustaining jarrah forest ecosystem that maintains the functions of the landscape prior to mining, including biodiversity, on areas that have been mined for bauxite. Indigenous terrestrial orchids form a significant proportion of the indigenous geophytic plant species that either fail to colonise rehabilitated areas or do so very slowly. Terrestrial orchids are considered to be particularly sensitive to competition from weeds and disturbance, which combined with the obligate nature of the orchid-mycorrhizal fungus association suggests that orchids would colonise rehabilitation areas only when both microhabitat sites and soil microflora have established. Occurrence of certain orchids may therefore be expected to be useful as indicators of ecosystem health, the success of vegetation establishment and the recovery of edaphic conditions suitable for orchid mycorrhizal fungi. Vegetation surveys were undertaken to compare orchid species richness and population size of a chrono-sequence of rehabilitation areas with adjacent unmined forest. ... Orchid taxa present in each vegetation assemblage were generally not exclusive to these assemblages, with the following broad exclusions: D. bracteata was found only in species assemblages associated with rehabilitation areas; and Eriochilus sp. and T. crinita were found only in species assemblages associated with unmined forest. No single orchid species appears to be an indicator of ecosystem recovery. However, the presence of populations of C. flava, P. sp. crinkled leaf (G.J.Keighery 13426) or P. recurva in combination with the absence of the disturbance opportunist orchid taxa D. bracteata and M. media appears to be a measure of the maturity of the rehabilitation vegetation. Orchid species richness and clonal orchid population size were correlated with changes in vegetation structure, but apart from the absence of orchids in 1 year old rehabilitation areas, these orchid population characteristics did not show any direct relationship with rehabilitation age or vegetation maturity. Only two orchid taxa appeared to have potential as indicators of vegetation characteristics: T. crinita as an indicator of undisturbed jarrah forest; and D. bracteata as an indicator of disturbed ecosystems. The results of this study suggest that most jarrah forest orchid taxa will readily colonise the post bauxite mining landscape, but that the unassisted colonisation by recalcitrant orchid taxa may be a prolonged process. It is recommended that field-based transplantation and/or seeding trials be undertaken with these recalcitrant taxa to determine if these procedures will enhance recruitment. The results of this work have applications not only in the management of post-mining landscapes but also in vegetation monitoring and conservation work in Western Australia and elsewhere.
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Lukasiewicz, Magdalena J. "Maternal investment, pollination efficiency and pollen, ovule ratios in Alberta orchids." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ48023.pdf.

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Schweiger, Julienne M. I. [Verfasser], and Gerhard [Akademischer Betreuer] Gebauer. "Partial mycoheterotrophy in orchids / Julienne M.-I. Schweiger ; Betreuer: Gerhard Gebauer." Bayreuth : Universität Bayreuth, 2019. http://d-nb.info/117852602X/34.

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Morris, Lynda M. "An analysis of the population genetics of orchids using protein electrophoresis." Thesis, University of Essex, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397368.

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Stökl, Johannes. "Pollinator driven radiation in sexually deceptive orchids of the genus Ophrys." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-60423.

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Ong, Jamie. "In bed with viruses: The partnership between orchids, fungi and viruses." Thesis, Ong, Jamie (2016) In bed with viruses: The partnership between orchids, fungi and viruses. PhD thesis, Murdoch University, 2016. https://researchrepository.murdoch.edu.au/id/eprint/37275/.

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The Orchidaceae is the largest and most diverse angiosperm family comprising of five subfamilies, over 800 genera and over 26,000 species. In Western Australia, there are over 450 indigenous orchid species across 40 genera, concentrated predominately within the South West Australian Floristic Region, but with a few species in the tropical Kimberley. The southern species are all terrestrial and most belong to the Diurideae tribe, which are primarily restricted to Australia and New Zealand. To varying degrees, orchids rely on associations with other organisms, particularly fungi for nutrient provision and insects for pollination. The partnerships between the orchids, their fungal symbionts and insect pollinators are quite well studied in some cases. However, the ecological influence of viruses, in particular indigenous viruses, within these symbiotic partnerships remains largely unexplored. Orchids cultivated for their flowers or vanilla are frequently infected by viruses, which are spread from plant to plant by vectors, husbandry tools and through vegetative propagation, and from place to place in infected propagules by trade. Only recently have wild orchids been shown to also harbour viruses. In this research, we used a combination of high throughput sequencing approach, traditional techniques and informatics to examine the leaf tissues of indigenous terrestrial orchid plants growing in their natural habitats for virus infection. Further, we isolated fungi that form mycorrhizal associations within cortical root cells of these plants and examined them for the presence of viruses. Terrestrial orchids and their fungal symbionts were sampled from 17 species across six genera (Caladenia, Diuris, Drakaea, Microtis, Paraceleana and Pterostylis) during the winter (June to August) and spring (September to November) growing seasons. This study represents the first of viruses from the indigenous orchids and fungal species examined. Thirty-two viruses, representing seven viral families and eight genera (Alphapartitivirus, Betapartitivirus, Endornavirus, Goravirus, Hypovirus, Mitovirus, Platypuvirus and Totivirus), were identified and characterised from wild plants of Drakaea, Microtis and Pterostylis orchids and their fungal symbionts. Four of the viruses were identified from leaves of Drakaea species and Pterostylis sanguinea orchids and the remaining 28 viruses were from six isolates of orchid mycorrhizal fungi of the genus Ceratobasidium. All but one of the viruses found were novel, and most were from taxonomic groups not previously described in the Australian continent. In three Ceratobasidium isolates studied, there were 5-13 virus species present in each. The presence of several closely-related bi-partite partitiviruses within the one host presented challenges in determining the numbers of species present and accurate pairing of virus segments. This study proposes solutions to address these problems, which will no doubt also arise in future metagenomics studies. Two of the new viruses described formed the bases of new genera (Goravirus and Platypuvirus), while other viruses could be tentatively classified within known taxa, but were often genetically divergent from existing members. For example, two novel partitiviruses represent a lineage basal to existing members of Alphapartitivirus, pointing to Australia as an important location in partitivirus evolution. The richness and uniqueness of viruses found in this study are likely a reflection of the orchid and fungal diversity of the region, itself a consequence of over 25 million years of relative geological and climatic stability. The surprisingly high numbers of mycoviruses detected from only a few fungal samples indicate that there is a rich virus association with fungal component of orchid biology and that orchid flora might represent a potentially enormous reservoir of novel viruses. geological and climatic stability. The surprisingly high numbers of mycoviruses detected from only a few fungal samples indicate that there is a rich virus association with fungal component of orchid biology and that orchid flora might represent a potentially enormous reservoir of novel viruses.
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Nguyen, Quang Duy. "Studies of Cryptostylis ovata and Microtis media orchids from Western Australia." Thesis, Nguyen, Quang Duy (2021) Studies of Cryptostylis ovata and Microtis media orchids from Western Australia. PhD thesis, Murdoch University, 2021. https://researchrepository.murdoch.edu.au/id/eprint/63106/.

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Cryptostylis ovata is the only evergreen indigenous orchid that grows in south-western Australia; all the others are deciduous. It uses a classical ‘k’ strategy to reproduce, thus it has a lifespan of decades or longer, and although it produces large numbers of seed when its flowers are pollinated, it appears that only a tiny proportion germinate. On the other hand, Microtis media is the classical ‘r’ breeder in that it lives typically from only one to a few years, and its flower spike generates thousands of seed, which freely germinate. We studied mycorrhizal associations in C. ovata and M. media plants from different wild plants at five sites per species, and at different times throughout the year and life cycles of the plants. Fungi were isolated from pelotons in the roots of both species, and pure cultures were obtained. Diagnostic sequences were generated from PCR products using primers annealing to conserved sequences flanking variable internal transcribed spacer (ITS) regions of the nuclear ribosomal gene. These studies indicated that C. ovata plants from five different sites maintained relationships with Tulasnella fungi of four distinct taxa. The associations were collection site-specific and clustered into two groups - the southern and northern groups. Fungal isolates collected from three southern C. ovata populations closely resembled T. prima isolates identified from Chiloglottis sp. orchids. Fungal isolates identified from two northern orchid populations were of three undescribed Tulasnella taxa. M. media plants collected from disturbed and undisturbed sites also associated with Tulasnella-like fungi. These Tulasnella-like fungi are different from those associated in C. ovata plants. There were six Tulasnella species identified from M. media roots, in which four taxa were similar to previously-described Tulasnella species. Two other taxa were predicted to belong to the families Serendipitaceae and Ceratobasidiaceae. We attempted to germinate C. ovata seeds using different natural and artificial media, and with different mycorrhizal fungal partners. Seeds that germinated to stage 3 (appearance of protomeristem) only occurred on oatmeal agar (OMA) media and soil solution equivalent (SSE) media inoculated with a Tulasnella prima isolate identified from C. ovata orchids, but not with those identified from M. media plants. OMA was the most promising media for C. ovata seed germination; seeds plated on this media inoculated with fungi derived from M. media plants got to stage 1 of germination (imbibed embryo). Unfortunately, none of the treatments in this study reached the final stage of germination—the appearance of the second leaf. Morphological characteristics of above-ground organs of C. ovata plants were recorded. Plants in southern populations had many relatively large dark-green leaves and flowers while plants in the two northern populations had smaller and fewer pale-green leaves and no flowers during the study times. Genetic diversity of all or most plants of the five populations was assessed using inter simple sequence repeat (ISSR) markers. Genetic analysis revealed that plants within each population clustered together, and each population was genetically-distinct from the others. Our findings suggested that at two sites, all plants were genetically-identical, suggesting only asexual reproduction occurred there. At the other three sites, there were varying degrees of genetic diversity, suggestive of sexual reproduction. The most sexually-diverse population was one growing within a pine plantation where few other plants could colonise. We discuss the implications of our research in terms of reproductive strategies in C. ovata, and factors that may limit sexual reproduction.
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LUSSU, MICHELE. "Patterns of reproductive isolation in Sardinian orchids of the subtribe Orchidinae." Doctoral thesis, Università degli Studi di Cagliari, 2019. http://hdl.handle.net/11584/260404.

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Abstract Orchids are globally well known for their highly specialized mechanisms of pollination as a result of their complex biology. Based on natural selection, mutation and genetic drift, speciation occurs simultaneously in organisms linking them in complexes webs called ecosystems. Clarify what a species is, it is the first step to understand the biology of orchids and start protection actions especially in a fast changing world due to human impact such as habitats fragmentation and climate changes. I use the biological species concept (BSC) to investigate the presence and eventually the strength of mechanisms that limit the gene flow between close related taxa. Islands are considered natural laboratories due their unique evolutionary trends which have led to a flora whose biology remains, in many cases, unknown and controversial. The main outcomes of this thesis are: i) clarify the number of orchid species currently recorded in Sardinia and discuss the relevance of studying orchids on island conditions; ii) adopting the biological species concept, investigate zygotic barriers in two endemic close related Ophrys species and iii) discuss the zygotic barriers in the two most important functional groups of deception in mediterranean orchids.
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佟穗海 and Shui-hoi Tung. "An ultrastructural study of megasporogenesis in oryza sativa, cymbidium sinense and phaius tankervilliae." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31214678.

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陳文頌 and Man-chung Chan. "Genetic diversity and relationships of spiranthes sinensis, S. spiralis, and S. hongkongensis (orchidaceae) as revealed by RAPD andcpDNA markers." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31214952.

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