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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.

A comparison of island and mainland pollination ecology

Spears, Edwin Eugene, January 1983 (has links)
Thesis (Ph. D.)--University of Florida, 1983. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 65-70).

A plant-pollinator network on Fårö island : description, comparison and general patterns

Johansson, Anna "Sixten" January 2012 (has links)
The overall aim of this study was to deepen the knowledge of multi-habitat networks. A broad array of basic aspects of the studied plant-pollinator network at Skalasand on the island of Fårö, Gotland was covered and compared witha similar study at the island of Gotska Sandön. The species composition differs considerably between the two networks. The Skalasand network has a richer faunaof insects belonging to the groups Syrphidaeand Apiformes, while Muscidae-flies constitute a considerable part of the Gotska Sandön network. However, the networks also have resembling modules. The modules are always established around one or a few plant species actingas hubs while animals visiting several habitats work as connectors linking the different modules. The Syrphidae and Apiformes are the two taxonomic groups that are the most generalistic when it comes to interacting in different habitats.

Isolation of expressed gene sequences from the stigma of Brassica oleracea

Booker, Jonathan Peter January 1996 (has links)
Molecular characterisation of the stigma and style in the Cruciferae has concentrated exclusively on the components of the SI system, and other members of their sequence families, while neglecting other sequences involved in tissue development and compatible pollination. To address this imbalance work has been carried out to isolate expressed gene sequences from the stigma of Brassica oleracea. cDNA clones were isolated from a cDNA library and characterised together with two clones isolated previously. Four out of eleven clones represented previously isolated S-gene and S-related gene sequences which have been extensively studied by other workers. One other sequence that could be positively identified encodes a putative glycine-rich cell wall protein which is expressed strongly in the stigma and more weakly in the style and petal, suggesting that it plays a specific role in the former. Of the other isolated clones, two cross-hybridise with closely related transcripts that are stress- induced in vegetative tissue. This allows parallels to be drawn with the Solanaceae, in which proteins, normally induced by stress, are also expressed in healthy carpels. However, the Brassica species differ from these in that they are expressed in all floral whorls. Neither stress-induced clone can be positively identified although their encoded proteins share homology with the major latex protein of poppy and two bacterial protein sequences. Of the remaining four sequences, two were enriched in stigmas, but contained insufficient sequence data to allow identification. The third sequence was expressed throughout the mature plant, though expression was higher in floral tissue, while expression of the fourth could not be determined. From these sequences no information concerning the molecular basis stigma development and function can be deduced. Therefore other approaches to studying this tissue are discussed.

The role of PCP-A class proteins in pollen-stigma interactions

Wingett, S. W. January 2002 (has links)
No description available.

Pollination, fruit set and identification studies in pear /

Sharifani, M. Mehdi. January 1997 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1999. / Includes bibliographical references (leaves 190-211).

Pollinators of slender white prairieclover

Pearce, April Marie. January 2008 (has links) (PDF)
Thesis (MS)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: Kevin O'Neill. Includes bibliographical references (leaves 95-102).

Pollination ecology of Trachymeme incisa (Apiaceae) understanding generalised plant-pollinator systems /

Davila, Yvonne Caroline. January 2006 (has links)
Thesis (Ph. D.)--School of Biological Sciences, Faculty of Science, University of Sydney, 2006. / Title from title screen (viewed 15 January 2009). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Includes bibliographical references. Also available in print form.

Pollination biology and pollinator alternatives in mermaid meadowfoam (Limnanthes alba Hartw. ex Benth.)

Jahns, Thomas R. 31 July 1990 (has links)
Meadowfoam (cultivar Mermaid) is an entomophilous winter annual oilseed crop that has historically produced an average of only two of five seeds per flower. Reference to inadequate meadowfoam pollination exists in the literature, but quantitative evidence is lacking. Studies were undertaken to: 1) quantify meadowfoam pollination requirements and 2) evaluate the potential of an alternative pollinator. In vivo pollination biology studies tested pollen age, stigma age, stylar restriction, and pollen deposition rate effects on seed set. Yield efficacy of Osmia lignaria propinqua Cresson, a native wild bee pollinator, was compared in cages to a honey bee standard and a non-caged honey bee control. Osmia reproductive potential was also tested. Pollen 0-5 days old (postanthesis), stored at 3, 18, or 37°C, did not appear to limit seed set. Stigma age was critical for seed set maximization. Seed set was not influenced by the number of stigmas pollinated per flower, but was limited by less than 25 pollen grains deposited per flower. Seed set and pollen deposition increased with increasing honey bee visits per flower. It was concluded that at least three honey bee colonies per acre should be used for commercial meadowfoam production. Osmia produced comparable individual plant yields to honey bees. Sixty Osmia produced similar solid stand yields to 4000 honey bees. Significantly greater solid stand yields per bee were obtained from Osmia when compared to the honey bee. Osmia survival and female production were negatively correlated with female density, while nest/male/total cell production was positively correlated with female density. Osmia demonstrated yield improvement potential as a meadow-foam pollinator. / Graduation date: 1991

Coleotrype madagascarica (Commelinaceae) : visual attraction and buzz pollination by anthophorid bees in Madagascar

Rubin, Miriam January 2015 (has links)
Little is known about the pollination in the spiderwort family, Commelinaceae. One of the species endemic to Madagascar, Coleotrype madagascarica C. B. Clarke, is an extremely ostentatious plant. With visual attraction such as basally coloured apical leaves, vividly coloured petals and an astounding fuzzy spherical hair structure on the stamens. The aim of the present study was to investigate the pollination system and reveal the effective pollinator of C. madagascarica. Field studies in central Madagascar indicated that the flowers attract a number of species of pollen seeking bees and flies. The pollination of C. madagascarica relies on female bees that buzz the fuzzy bright yellow stamen filament hairs and later deposit pollen on the stigma topping the ventrally protruding hook shaped style of another flower. During a visit, the bee grabs on to the stamens and vibrate its flight muscles to eject pollen from the anthers. Anthophorid bees, especially Amegilla and Pachymelus, were the most frequent visitors and apparent pollinators.

Studies on the pollination biology and breeding systems of some genera with sympatric species in the Brazilian cerrados

Barros, Mariluza Araujo Granja e January 1990 (has links)
Flowering phenology, floral strategies pollinator activity and breeding system were investigated in 14 species of the cerrado vegetation in Braeflia (DF), from April 1985 to April 1986 in Tabebuia caraiba (Mart.) Bur., T. ochracea (Cham.) Standl.; Erythroxylum campestre St. Hil., E. suberosum St. Hil., E. tortuosum Mart.; Diplueodon crulsianue Pohl., D. oblongus Pohl., D. ramosissimus Pohl., D. roomarinifolius St. Hil., D. villosus Pohl.; Kielneyera abdita Saddi, K. coriacea Mart., K. speciosa St. Hil. and K. variabilis Mart. The species occur sympatrically, often only a few meters apart, and conspecifics frequently occur in clumps. The majority of the species flowered during the dry season (May to August) except D. oblongue, D. villosue and K. speciosa which flowered during the wet season (December to March). Most of them flowered for several months except Tabebuia (one month). The most frequent flowering pattern was the "Cornucopian"' type, except for D. crulsianue and D. Villosus which were "Steady-State" types. Most congeners flowered synchronously, except K. speciosa which showed displacement. Flowers of all species are pollen donors (Tabebuia and Erythroxylum also have nectar rewards), but each genus presents specific floral strategies; Tabebuia, Massflowering, Erythroxylum, distyly and cauliflory, Diplueodon, enantiostyly and Kielmeyera, andromonoecy. Flowers were visited by a large spectrum of bees (38spp. ) and Erythroxylum were also visited by wasps (16 app. ). However, each genus had particular pollen vectors. Tabebuia; Centris and Bombus; Erythroxylum: wasps; Diplueodon; Apia and Trigona; and Kielmeyera; Xylocopa, despite the fact that other bees occur all year round. Controlled pollination experiments (self-, intraspecific-, interspecific crosses, tests for apomixis and from untreated bagged flowers), revealed that all species have a high outcrossing level and are selfincompatible. Only E. campeatre (shrub), D. crulsianus and D. villosus (hemixyles), showed some self-compatibility. Fluorescence microscopy indicated that pollen tubes from selfing and from interspecific cross pollinations were blocked in the ovary, suggesting that the selfincompatibility barrier operates late. Only in Erythroxylum the blockage occurred in the stigma (Thrum flowers) or in the style (Pin flowers). Fruit-set number from hand-pollinations and from natural pollination were low, but the former frequently yielded a higher number of fruits than the latter. Low fruit-set was associated with lack of resources allocated by the maternal parent for fruit maturation. In addition, it seemed that, in all species, many flowers were programmed to be pollen donors only, since they dropped without any sign of ovary enlargement even if they were hand-pollinated or were frequently visited by pollinators.

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