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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Some effects of photoperiod and alternating temperature on root and shoot development of Lilium tigrinum bulbils

Wilson, Kenneth E January 2010 (has links)
Digitized by Kansas Correctional Industries
2

The origin and development of bulbs in the genus Erythronium ...

Blodgett, Frederick H. January 1910 (has links)
Thesis (Ph. D.)--Johns Hopkins University. / Biographical note. Reprinted from the "Botanical gazette," vol. 50, 1910. Published also as Contributions from the Botanical laboratory of the Johns Hopkins university no. 14. Literature cited: p. 371.
3

Bulbs for Northern Arizona

Allen, Alvin., Tate, Harvey F. 06 1900 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.
4

Some effects of magnesium and boron on King Alfred daffodil bulbs forced in a Fraser Valley 'problem' soil

Dennis, Mary Mulvin January 1952 (has links)
A commercial bulb growing concern in the Cloverdale section of the Lower Fraser Valley, British Columbia, has been experiencing recently a severe reduction in tonnage of mature bulbs produced. Because of premature ripening of the foliage, the bulbs do not attain an optimum increase in size and weight. The loss is considered to be over fifty percent reduction in crop yield. A bulb forcing experiment was set up in the University of British Columbia greenhouse in order to ascertain the effects of boron and magnesium on the growth and yield of bulbs produced on the Cloverdale farm. Soil, from the farm was used for four sets of flats planted with comparable lots of bulbs; a fifth set of flats was planted, using U.B.C. unfertilized greenhouse soil. The four sets of flats filled with the 'problem' soil were treated as follows: one series of flats was left untreated, a second series was treated with boric acid at the rate of 50 pounds to the acre, a third series was treated with magnesium sulphate at the rate of 200 pounds to the acre and the fourth series, was left until foliar growth was established and at that time was sprayed with a boric acid spray of 100 ppm boron concentration. The bulbs were planted in November and brought into the greenhouse from cold frames in late January for forcing. After the daffodils had bloomed, the flats were placed outside for the ripening off of the foliage. No early die-back occurred and the bulbs were lifted in June. After the bulbs had been dried, they were cleaned and weighed. Increases in yield for each treatment were calculated and analysed statistically. It was found that boron as a foliar spray of 100 ppm had a detrimental effect on bulb weight increase, and. that boron applied as a fertilizer at the rate of 50 pounds, to the acre had no beneficial effect. Magnesium sulphate applied to the soil, at a rate of |00 pounds to the acre, to the 'problem' soil had a significant effect on bulb weight increase of the King Alfred daffodil bulbs forced in the greenhouse. / Land and Food Systems, Faculty of / Graduate
5

Onderzoekingen over schimmelziekten van Bolgewassen

Feekes, Franciskus Henri. January 1931 (has links)
Thesis (doctoral)--Rijksuniversiteit te Utrecht, 1931. / Bibliography: p. [91]-93.
6

Studies in the South African Bulbous liliaceae

Jessop, John Peter January 1973 (has links)
The work comprises two principal sections; an attempt at ellucidating generic relationships in the South African bulbous Liliaceae, and a revision of the species of selected genera. In the first section the approaches investigated were: 1) A re-evaluation of the nature of the bulb apex, showing a likelihood that certain groups possess axillary and other groups terminal inflorescences. 2) An investigation of leaf anatomy, showing that most genera have very similar leaf structure, but that a few genera do differ from this norm. Scilla (Euscilla) generally possesses a distinctly lignified bundle sheath and the Urginea-Drimia group show a great range in structures - including a palisade. 3) An impression technique to determine patterns in the surface of the leaf cuticle. A close correlation appears to exist between these patterns and leaf shape. 4) Scanning Electron Microscope pictures of pollen revealed a considerable uniformity within the group and between this group and most other members of the Liliaceae. 5) Scanning Electron Microscope pictures of seeds revealed two main groups in the bulbous Liliaceae determined on the appearance of the cell walls of the testa. 6) A simple chromatographic technique was not found to be useful. 7) An investigation of chromosome numbers of. 44 samples of 15 species supplemented published data in allowing an analysis to be made of the application of chromosome numbers to generic concepts. Many genera of the Liliaceae - especially in the bulbous group - have extremely variable chromosome numbers. It is considered that numbers are more applicable to tribal than to generic concepts. Few indications of meiotic abnormalities were detected. Phylogenetic and taxonomic aspects of the genera of the bulbous Liliaceae are discussed and a key to the South African bulbous Liliaceae genera constructed. The following generic alterations are proposed: Ledebouria to be split off Scilla. Schizocarphus to be placed in Scilla. Resnova to be placed in Drimiopsis. The Astemme section (= Neobakeria) to be removed from Polyxena and placed in Massonia. The Cape species of Hyacinthus to be placed in Polyxena. Thuranthos, Urgineopsis and Urginea to be placed in Drimia. It is suggested that Schizobasis and Bowiea are of great importance in explaining the origin of Asparagus - possibly even directly from this group. In the generic revisions, thirteen genera are dealt with including typification, synonymy, distribution, field notes, species descriptions and keys. 67 species are dealt with, of which three are new (all in Ledebouria), and 31 new combinations are proposed.
7

Systematic significance of bulb morphology of the Southern African members of Oxalis L. (Oxalidaceae)

Gebregziabher, Awot Kiflu 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: The systematics of the southern African members of the genus Oxalis L. (Oxalidaceae) is in a state of flux. The bulbs of these species contain potential taxonomically important characters and therefore require detailed study (Salter, 1944). A pilot study assessed the homology of bulbs among southern African Oxalis species (Gebregziabher, 2001), and found that they are all homologous structures. This pilot study also emphasized the range of potentially informative characters from different bulb parts. The aim of the present study was to assess the taxonomic significance of bulb morphology in selected southern African Oxalis species. As far as possible, efforts were made to represent both the taxonomic (Salter, 1944) and palynological diversity (Dreyer, 1996) present in the genus. Detailed bulb morphological studies of 30 species of southern African Oxalis species revealed 41 potentially informative characters. Different bulb-types were identified based on these characters. Bulb-type affinities of taxa included in this study, as well as bulb descriptions from the pilot study (Gebregziabher, 2001), were discussed. Comparison with the current taxonomic classification (Salter, 1944), palynological classification (Dreyer, 1996) and a preliminary phylogeny based on the non-coding plastid trnL-trnF DNA region (Oberlander, 2003), were also made. Bulb morphology conflicted with the current taxonomic classification (Salter, 1944), but showed greater congruence with both the palynological groupings and the trnL-trnF based phylogeny. Based on this study, bulb morphology is found to be taxonomically significant. Further studies on the bulb morphology and anatomy of southern African Oxalis species are merited. Key words: bulb morphology, Oxalis, informative characters, basal plates, fleshy leaves, tunics / AFRIKAANSE OPSOMMING: Die sistematiek van die suider Afrikaanse lede van Oxalis L. (Oxalidaceae) is labiel. Die bolle van hierdie spesies sluit potensieel taksonomies belangrike kenmerke in, en behoort daarom in detail bestudeer te word (Salter, 1944). In Loodsstudie het die homologie van die bolle van die suider Afrikaanse Oxalis spesies ge-evalueer (Gebregziabher, 2001), en gevind dat hulle homoloë strukture is. Resultate van hierdie loodsstudie het ook die reeks van potensieel informatiewe kenmerke van verskillende boldele beklemtoon. Die doel van hierdie studie was om die taksonomiese belang van boImorfologie in geselekteerde suider Afrikaanse Oxalis spesies te ondersoek. Pogings is aangewend om, sover moontlik, beide die taksonomiese (Salter, 1944) en die palinologiese (Dreyer, 1996) diversiteit van die genus in die studie in te sluit. Gedetailleerde bol-morfologiese studies van 30 suider Afrikaanse Oxalis spesies het 41 potensieel informatiewe kenmerke uitgewys. Gebaseer op hierdie kenmerke, is verskillende bol-tipes geïdentifiseer. Verwantskappe tussen die bol-tipes van die spesies ingesluit in hierdie studie, sowel as beskrywings van bolle volgens die loodsstudie (Gebregziabher, 2001), word bespreek. Vergelykings met die huidige taksonomiese klassifikasie (Salter, 1944), palinologiese klassifikasie (Dreyer, 1996) en In voorlopige filogenie gebaseer op die niekoderende plastied trnL-F DNA-streek (Oberlander, 2003) is ook getref. BoImorfologie weerspreek die huidige taksonomiese klassifikasie (Salter, 1944), maar toon groter ooreenstemming met beide die palinologiese groeperings en die trnL-F gebaseerde filogenie. Hierdie studie het bevind dat bolmorfologie van taksonomiese waarde is. Verdere studies op die bolmorfologie en -anatomie van die suider Afrikaanse Oxalis spesies word aanbeveel.
8

Seasonal pharmacological and phytochemical properties of medicinal bulbs.

Ncube, Bhekumthetho. January 2010 (has links)
Medicinal bulbs form part of the diversified flora in South Africa. The plants are used extensively in South African traditional medicine in the treatment of various ailments. Due to the ever-increasing demand and the unrestricted collection of medicinal plants from the wild, many of these slow growing bulbous plant species are driven into over-exploitation and extinction. The main parts collected for use are the underground bulbs, leading to the destructive harvesting of the whole plant. This form of plant harvesting poses threats to the long term sustainability of these plant resources from their natural habitats. Sustainable harvesting of these plants should be within the limits of their capacity for self-renewal. However, this seldom occurs with the often inconsiderate medicinal plant gatherers. Conservation of these plants is therefore necessary. A strategy that would take into consideration the sustainable harvesting and perhaps simultaneously provide similar medicinal benefits, would be the substitution of bulbs with leaves of the same plant. This study was aimed at evaluating the seasonal pharmacological and phytochemical properties in bulbs/corms and leaves of medicinal bulbs with a view of promoting the substitution of bulbs with leaves in traditional medicinal use. Four medicinal bulbous plants, Tulbaghia violacea, Hypoxis hemerocallidea, Drimia robusta and Merwilla plumbea were evaluated for the pharmacological and phytochemical properties in their bulbs/corms and leaves in spring, summer, autumn and winter seasons, with a view of promoting the use of leaves as a conservation strategy. Dried plant materials were sequentially extracted with petroleum ether (PE), dichloromethane (DCM), 80% ethanol (EtOH) and water in each season. The extracts were tested for activities against Gram-positive (Bacillus subtilis and Staphylococcus aureus), Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacteria and the fungus Candida albicans using the in vitro microdilution assays to obtain minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC). The four plant species were also evaluated for their ability to inhibit cyclooxygenase (COX-1 and COX-2) enzymes. Spectrophotometric methods were used to evaluate saponin and phenolic contents of samples from the four plant species in each season. Antibacterial activity was fairly comparable between bulbs/corms and leaves of H. hemerocallidea, T. violacea, and M. plumbea, with at least one extract showing some good activity (MIC < 1 mg/ml) in most of the seasons. Bulb extracts of D. robusta did not show good antibacterial activity while the leaf extracts showed good activity (0.78 mg/ml) against B. subtilis in spring, summer, and autumn and S. aureus (0.78 mg/ml) in autumn. The best antibacterial activity was recorded in winter, with MIC values as low as 0.195 mg/ml from the DCM bulb extracts of T. violacea against K. pneumoniae and S. aureus and PE corm extracts of H. hemerocallidea (0.195 mg/ml) against B. subtilis. Good antibacterial activity from water extracts were only recorded from corm extracts of H. hemerocallidea in summer, autumn and winter, H. hemerocallidea leaf extracts in autumn and winter, and M. plumbea bulb extracts in autumn. The leaf extracts of all the screened plant species demonstrated good fungicidal activity in autumn, with H. hemerocallidea corm water extracts recording an MFC value as low as 0.39 mg/ml. The leaf extracts of H. hemerocallidea (water), D. robusta (DCM) and M. plumbea (DCM) had good MFC values of 0.78 mg/ml each, in spring. The DCM leaf extracts of T. violacea also showed good fungicidal activity (0.78 mg/ml) in summer, while corm water extracts of H. hemerocallidea had an MFC value of 0.39 mg/ml in winter. There were no fungicidal activities recorded from all the bulb extracts in all the seasons. All the PE and DCM extracts in all the tested plant samples recorded between moderate (40-70%) and high (> 70%) COX-1 and COX-2 inhibition levels across all seasons. The EtOH corm extracts of H. hemerocallidea also demonstrated moderate to high inhibitory activity against COX-1 enzyme across all seasons. Bulb and leaf extracts of T. violacea showed selective inhibitory activity for COX-2 enzyme in all the seasons. The highest COX inhibitory levels were recorded in COX-2 from the PE leaf (spring) and bulb (autumn) extracts of T. violacea, with both recording 100% inhibitory activity. Phytochemical analysis revealed higher total phenolic compounds in bulbs/corms and leaves of all the analysed plant species, to be either higher in spring or winter. Plant material collected in autumn had the least levels of total phenolics. An almost similar trend to that of total phenolics was observed for flavonoids, gallotannins and condensed tannins in most plant samples, with higher levels either in spring or winter. Total saponins were consistently higher in winter than in the other seasons in all the screened plant species. There were in some cases, relationships between the peaks in the levels of some phytochemical compounds and the observed levels of bioactivity in different assays. The results obtained from this study demonstrate that the leaves of the screened plant species may substitute or complement bulbs in the treatment of certain ailments in traditional medicine. Thus, plant part substitution can be sustainably utilised in the conservation of these plant species while retaining the same medicinal benefits. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.
9

Micropropagation of Brunsvigia undulata F.M. Leight.

Rice, Laura Jane. January 2009 (has links)
Many South African medicinal plants face the threat of over-collection for use in traditional medicines. Many bulbous plants suffer as the whole plant is removed from the wild so that the bulb may be used for medicine. Micropropagation is a technique which can be used as an alternative to conventional propagation methods. Micropropagation produces many plantlets in a relatively short period of time. Different plant parts of Brunsvigia undulata F.M. Leight, a rare South African species of medicinal value, were used in an attempt to produce in vitro plantlets using micropropagation techniques. Although leaf and floral explants were successfully formed from seedling explants and twin-scales. Seeds germinated quickly in culture. Seedlings which grew from seeds were cut into sections and used to initiate bulblets. Seedling explants formed bulblets, shoots and callus best when the explants included a meristematic region. Callus from seedling explants formed shoot clusters readily when placed on hormone-free MURASHIGE and SKOOG (1962) (MS) medium. Shoots from shoot clusters formed bulblets and rooted on medium supplemented with IBA. The greatest rooting response was achieved by bulblets on 1 mgl-1 IBA. The callus which was left after shoot clusters were separated was placed back onto hormone-free MS medium. Callus explants continued to form shoot clusters. Twin-scales, cut from large parent bulbs, were cultured on 25 hormone treatments. Bulblets formed on twin-scales even in the absence of plant growth hormones. Bulblets formed by twin-scales were used to determine the effects of both medium constituents and environmental factors on bulblet multiplication. Bulblet multiplication was greatest when bulblets were split in half and cultured as half-bulblets. Optimal multiplication was achieved on hormone-free MS, with 4% sucrose, kept at high temperatures in the dark. Bulblets were successfully initiated and multiplied from both seedlings and twin-scales. Bulblets which were produced via both protocols were acclimatized relatively easily. Both explant types could be used to mass propagate Brunsvigia undulata. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
10

In vitro bulb induction in Eucomis zambesiaca Baker.

Cheesman, Lee. January 2009 (has links)
Eucomis L’ Hér. is a genus of 10 species that fall within the Hyacinthaceae family. Eucomis zambesiaca Baker is a summer-blooming bulbous geophyte occurring from northern South Africa to Malawi. Eucomis species are used in southern African traditional medicine for the treatment of various ailments, in particular, pain and inflammation. As a result, the bulbs are heavily harvested for trade in South Africa’s traditional ‘muthi’ markets. Over-collection of Eucomis species has seriously depleted natural populations and now Eucomis plants are among the 15 scarcest medicinal species to be traded. Micropropagation is a useful technique for rapid clonal multiplication of plant material which could potentially yield useful secondary metabolites as well as alleviate the pressure on the wild plant populations. The in vitro induction of storage organs is especially beneficial as it can limit the loss of plants during acclimatization as bulblets are hardier than shoots or plantlets. The aim of this research was to determine optimal growth conditions for bulblet induction of Eucomis zambesiaca. The effect of environmental and physiological parameters on the initiation and growth of bulblets was investigated. These included the effect of temperature, photoperiod, various carbohydrates at different concentrations and combinations as well as various plant growth regulators. Maximum number of bulblets per explant was obtained at 20 °C, with an average of three bulbs p er leaf explant. The average bulblet mass was 57 mg, which was significantly higher than bulblets formed at other tested temperatures. An 8 h light regime was the optimum photoperiod. The highest mean number of bulblets (1.4 per leaf explant) developed under the 8 h photoperiod and the bulblets that formed were large in size. They had a mean bulb diameter of 3.4 mm and a mean bulb weight of 42 mg. Different carbohydrates such as fructose, sucrose and glucose were tested at concentrations of; 1, 3, 6, 9 and 12%. Fructose at a concentration of 3% was found to produce the best results. An average of 1.2 bulbs formed per explant. The mean bulb diameter was 3.4 mm and mean bulb weight was 56.6 mg. Plant growth regulators (GA3, IAA, IBA, NAA, BA, zeatin, iP and others) were tested at concentrations of 1, 2 and 5 mg/L. 1 mg/L IBA was found to be the optimum hormone treatment for bulblet induction. Bulblets were large, had good leaves and well established roots. Medium supplemented with 1 mg/L IBA produced bulblets that had an average bulb diameter of 4.36 mm and a mean bulblet weight of 79.1 mg. Bulblets grown in vitro were transferred to vermiculite and placed in a misthouse to acclimatize. After 2 months the plantlets were transferred to pots containing a sand:soil mixture of 1:1 and placed in a greenhouse. There was a 80 to 90% survival rate. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

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