Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"Gametophytes"”.
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A biological study of Desmarestia firma (C.Ag.) Skottsb. (Phaeophyceae, Desmarestiales)
… rise to separate filamentous male and female gametophytes. Male gametophytes bear flask-shaped antheridia, each containing a single antherozooid. Female gametophytes bear club-shaped oogonia, each producing one or perhaps more eggs. Trichothallic sporophytes are fused to the female …
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Tolerance and Accumulation of Copper, Lead and Zinc by Ceratopteris richardii
… evaluated the ability of Ceratopteris richardii gametophytes and sporophytes to tolerate copper, lead and zinc and for the sporophytes to accumulate the three metals in their shoots. Spores were sown in plant medium treated with varying concentrations of Cu, Pb and Zn. Fifteen-day- old …
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Elevated temperatures create bottlenecks in the life history of bull kelp (Nereocystis luetkeana, Phaeophyceae)
… (10, 12, 15, and 18°C) on the development of gametophytes and young sporophytes cultured from field-collected sori over four weeks. The density of female gametophytes declined significantly at 15°C and 18°C, while the density of male gametophytes remained consistent across temperatures, …
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Profiling gene expression during early gametophyte development and sex determination in Ceratopteris richardii
… and induces male development in other juvenile gametophytes. Our goal is to better understand the genetic and molecular mechanisms involved in sex determination and to identify sex determination genes in Ceratopteris. RNA-Seq was used to create <em>de novo</em>transcriptome assemblies from …
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The biosystematics of pteridophytes: aspects of morphology and reproductive biology of some epiphytic ferns
<p>Characteristics of fern gametophytes relate to their habitats. Epiphytic habitats are generally covered by bryophyte mats, making a challenging environment for sporophyte production by resident fern gametophytes. Gametophyte morphology and reproductive biology of several epiphytic ferns, …
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PHYSIOLOGICAL STUDIES USING TISSUE CULTURES OF PLATYCERIUM CORONARIUM (KOENIG) DESV
… ferns. Apogamous sporophytes were produced on gametophytes cultured in the presence on 40 µM indole-3-acetic acid (IAA). When ethylene was allowed to accumulate in the culture vessels in the presence of IAA, the frequency of regeneration and the total number of apogamous sporophytes producted …
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Chemical and biological control of silvery threadmoss on creeping bentgrass putting greens
… were conducted to examine the growth of moss gametophytes from spores and bulbils and to evaluate turf protection products for pre and postemergence moss control. Moss gametophytes develop best from spores at 30"aC and from bulbils at 23"aC. Products which control moss equivalent to …
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The development of Mazzaella capensis (J.Ag.) Fredericq in culture, in the field, and the effect of environmental factors
… from tetrasporophytes in early winter to gametophytes in early summer, corresponding with an increase in biomass. It was concluded that the new recruits were mostly gametophytes and that their increase relative to the perennating tetrasporophytes was responsible for the switch in …
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Restoration of lowland raised bogs damaged by peat extraction - with particular emphasis on Sphagnum regeneration.
… more prolifically from fragments than intact gametophytes. Sphagnum rafts are encouraged in shallow water (< 5 0cm) and pools of small area. Numerous management options exist physically and chemically assisting raft development.
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The potential of Grateloupia filicina (Lamouroux) J. Agardh. for mariculture: culture experiments and observations on shore phenology
… were found in September. No male gametophytes or spermatangia were found. It did not emerge from this study whether G. filicina in an annual, or what phenotypic differences are found throughout the year. Information of this kind is important for mariculture as it affects the supply …
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Physiological effects of climate change and estimations of carbon standing stock of southern Salish Sea kelps
… In our second experiment, we exposed microscopic gametophytes from the same two populations to a fully crossed experiment manipulating temperature (12 and 18 C) and pH (8.0 and 7.5) for one month. Because the gametophyte stage governs reproduction, recruitment, and long-term population …
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The Control of Spore Germination in Anemia Phyllitidis (L.) Swartz and Other Ferns
… requirement and induce dark-germination. Fern gametophytes produce antheridium-inducing substances. The Anemia substance, antheridogen-B, is demonstrated to induce germination in two genera of the Schizaeaceae, Anemia and Mohria. The Pteridium substance, antheridogen-A, stimulates germination …
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COMPARATIVE ULTRASTRUCTURE OF APICAL CELLS AND DERIVATIVES IN BRYOPHYTES, WITH SPECIAL REFERENCE TO PLASMODESMATA
… patens gametophores. The PD densities of gametophytes examined in this study fall into the lineage-specific network of PD (LPD) group designated for sporophytes of monilophytes and Selaginella (heterosporous lycophyte) with single ACs. Takakia lepidozioides leafy shoot has a tetrahedral AC …
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Tropical bracken, a powerful invader of pastures in South Ecuador: Species composition, ecology, control measures, and pasture restoration
… sporophytes were observed. These developed from gametophytes, which germinated from the wind dispersed spores. Fast growth of the young sporophytes established the fern in the areas. After planting pasture grass, bracken was supported by repeated burning of the areas. In the long run, the grass …