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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.
21

Avaliação do potencial fisiológico de sementes de mutamba (Guazuma ulmifolia Lam.) por meio de diferentes testes de vigor

Gonçalves, Edilma Pereira [UNESP] 17 February 2003 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:33:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-02-17Bitstream added on 2014-06-13T19:04:46Z : No. of bitstreams: 1 goncalves_ep_dr_jabo.pdf: 289095 bytes, checksum: 7269bd2d477247a23b6cbac1169ace2c (MD5) / O trabalho teve como objetivo verificar a eficiência de diferentes testes de vigor para identificação do potencial fisiológico de quatro lotes de sementes de mutamba (Guazuma ulmifolia Lam.). O estudo foi desenvolvido no Laboratório de Análise de Sementes e no Viveiro Experimental de Plantas Ornamentais e Florestais - UNESP, Jaboticabal, SP. Foram utilizados quatro lotes de sementes provenientes de três localidades paulistas: lotes I e 11, coletados no município de Jaboticabal em 2000 e 2001, respectivamente, lote 111, coletado em Santa Rita do Passo Quatro, e lote IV, coletado em Luiz Antonio, os dois últimos em 2001. As sementes utilizadas em todos os testes foram escarificadas com ácido sulfúrico durante 50 minutos e lavadas em água corrente durante 15 minutos. Foram avaliados: teor de água, teste de germinação, teste de primeira contagem, índice de velocidade de germinação, emergência em viveiro, índice de velocidade de emergência, envelhecimento acelerado conduzido nas temperaturas de 410e e 450e, durante nove períodos de avaliação, e condutividade elétrica com diferentes números de sementes (50, 75, 100), postas para embeber em copos de plástico contendo 50, 75 e 100 mL de água desionizada, à temperatura de 250e, fazendo leituras freqüentes durante 72 horas. Os teores de água das sementes nos diferentes lotes apresentaram pequenas variações (9,2 a 10,0 %). Não foram verificadas diferenças estatísticas para a porcentagem de germinação, emergência em viveiro e índice de velocidade de emergência. Diante dos resultados obtidos, concluiu-se que o envelhecimento acelerado pode ser realizado na temperatura de 41°C por um período mínimo de 120 horas ou a 45°C durante 96 horas para avaliação do potencial fisiológico, e o teste de condutividade elétrica não se mostrou adequado para avaliação do potencial fisiológico das sementes... / The work had as objective to compare the efficiency of different vigor tests for identification of the physiologic potential in four lots of Guazuma ulmífolia seeds. The experiments were carried out at Jaboticabal, State of São Paulo, Brazil. Four seed lots from three places of São Paulo State were used: lots I and 11, collected in the municipal district of Jaboticabal in 2000 and 2001, lot 111, collected in Santa Rita do Passa Quatro, and lot IV, collected in Luiz Antonio, the last two in 2001. The seeds used in ali the tests were escarified with sulfuric acid during 50 minutes, and washed in running water during 15 minutes. The results were evaluated with base on seed moisture content, germination test, first count test, germination speed index, emergency in nursery, emergency speed index, accelerated aging at the temperatures of 41°C and 45°C (nine evaluation periods of time) and electric conductivity with different numbers of seeds (50,75, 100), put to soak in plastic boxes containing 50, 75 and 100 mL of water, at 25°C, with frequent observations during 72 hours. The seed moisture content in the different lots presented small variations (9,2 to 10,0%). Statistical differences were not verified for the germination percentage, emergency in nursery and emergency speed index. It was concluded that the accelerated aging at 41°C during a minimum period of 120 hours or at 45°C during 96 hours can be used for evaluation of the physiologic potential of the seeds, and the test of electric conductivity was not appropriate for this purpose. The test of first count and index of germination speed showed to be adequate for evaluation of the physiologic potential of the lots. The germination tests, emergency in nursery and index of emergency speed did not detect differences in the physiologic potential of the studied lots. The seeds lot from Santa Rita do Passa Quatro presented physiologic potential superior to the other lots.
22

Avaliação do potencial fisiológico de sementes de mutamba (Guazuma ulmifolia Lam.) por meio de diferentes testes de vigor /

Gonçalves, Edilma Pereira. January 2003 (has links)
Orientador: Maria Esmeralda Soares Payão Demattê / Banca: Teresinha de Jesus Deléo Rodrigues / Banca: Sonia Cristina Juliano Gualtieri de Andrade Perez / Banca: Rosiris Bergemann de Aguiar Silveira / Banca: Rinaldo Cesar de Paula / Resumo: O trabalho teve como objetivo verificar a eficiência de diferentes testes de vigor para identificação do potencial fisiológico de quatro lotes de sementes de mutamba (Guazuma ulmifolia Lam.). O estudo foi desenvolvido no Laboratório de Análise de Sementes e no Viveiro Experimental de Plantas Ornamentais e Florestais - UNESP, Jaboticabal, SP. Foram utilizados quatro lotes de sementes provenientes de três localidades paulistas: lotes I e 11, coletados no município de Jaboticabal em 2000 e 2001, respectivamente, lote 111, coletado em Santa Rita do Passo Quatro, e lote IV, coletado em Luiz Antonio, os dois últimos em 2001. As sementes utilizadas em todos os testes foram escarificadas com ácido sulfúrico durante 50 minutos e lavadas em água corrente durante 15 minutos. Foram avaliados: teor de água, teste de germinação, teste de primeira contagem, índice de velocidade de germinação, emergência em viveiro, índice de velocidade de emergência, envelhecimento acelerado conduzido nas temperaturas de 410e e 450e, durante nove períodos de avaliação, e condutividade elétrica com diferentes números de sementes (50, 75, 100), postas para embeber em copos de plástico contendo 50, 75 e 100 mL de água desionizada, à temperatura de 250e, fazendo leituras freqüentes durante 72 horas. Os teores de água das sementes nos diferentes lotes apresentaram pequenas variações (9,2 a 10,0 %). Não foram verificadas diferenças estatísticas para a porcentagem de germinação, emergência em viveiro e índice de velocidade de emergência. Diante dos resultados obtidos, concluiu-se que o envelhecimento acelerado pode ser realizado na temperatura de 41°C por um período mínimo de 120 horas ou a 45°C durante 96 horas para avaliação do potencial fisiológico, e o teste de condutividade elétrica não se mostrou adequado para avaliação do potencial fisiológico das sementes... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The work had as objective to compare the efficiency of different vigor tests for identification of the physiologic potential in four lots of Guazuma ulmífolia seeds. The experiments were carried out at Jaboticabal, State of São Paulo, Brazil. Four seed lots from three places of São Paulo State were used: lots I and 11, collected in the municipal district of Jaboticabal in 2000 and 2001, lot 111, collected in Santa Rita do Passa Quatro, and lot IV, collected in Luiz Antonio, the last two in 2001. The seeds used in ali the tests were escarified with sulfuric acid during 50 minutes, and washed in running water during 15 minutes. The results were evaluated with base on seed moisture content, germination test, first count test, germination speed index, emergency in nursery, emergency speed index, accelerated aging at the temperatures of 41°C and 45°C (nine evaluation periods of time) and electric conductivity with different numbers of seeds (50,75, 100), put to soak in plastic boxes containing 50, 75 and 100 mL of water, at 25°C, with frequent observations during 72 hours. The seed moisture content in the different lots presented small variations (9,2 to 10,0%). Statistical differences were not verified for the germination percentage, emergency in nursery and emergency speed index. It was concluded that the accelerated aging at 41°C during a minimum period of 120 hours or at 45°C during 96 hours can be used for evaluation of the physiologic potential of the seeds, and the test of electric conductivity was not appropriate for this purpose. The test of first count and index of germination speed showed to be adequate for evaluation of the physiologic potential of the lots. The germination tests, emergency in nursery and index of emergency speed did not detect differences in the physiologic potential of the studied lots. The seeds lot from Santa Rita do Passa Quatro presented physiologic potential superior to the other lots. / Doutor
23

Predicting forest cover types in Southwestern Virginia using topographic information

Fies, Michael Lawrence January 1983 (has links)
A computerized clustering algorithm, DIVIDE, was used to gain insight into the relationships between physical site factors and existing forest communities in southwestern Virginia. A pair of dichotomous keys was produced that "predicted" the forest type most likely to occur in an area based on topography. Maps of predicted forest types, using the Trayis (1982) and SAF (1980) vegetation classification systems, were produced for the entire study area. Accuracy levels of 57 to 78 percent were obtained. There were no significant differences in classification accuracy between Trayis and SAF forest type predictions (P > 0.25). Herbaceous understory was sampled on the basis of cover, and mast production was estimated in each of the forest types. Forest types on sites had significantly greater amounts of forb and fern cover than those on drier sites. Production of grasses and leaves of woody plants was probably similarly affected, but differences were not significant. Estimates of acorn production were highest in old stands containing a high percentage of oaks. Oak stands on moist sites appeared to have higher estimated mast yields than those on dry sites, but differences were not significant. Based on the results of these analyses, forest types were rated tor deer suitability using compatibility matrices. Deer habitat suitability maps vere produced for the entire study area based on these matrices. Differences between overall suitability values for the Travis and SAF systems suggest that selection of an appropriate forest type classification system is important for wildlife managers. / M.S.
24

Forest vegetation and fuel dynamics following stand-replacing wildfire, re-burn, and postfire management in the Siskiyou Mountains, Oregon /

Donato, Daniel C. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 172-187). Also available on the World Wide Web.
25

The Spatial Effects of Road Use Intensity on Forest Plant Communities and Soil Chemistry

Asmussen, David 19 July 2011 (has links)
Roads alter the ecological landscape and affect the function and composition of nearby soil chemistry and plant communities in an area of impact termed the “edge-effect zone”. While the 6.3 million kilometers of roads in the US cover only about 1% of the land, the edge effect zone around these roads has been estimated to occupy nearly 20% of the total land area in the US (Forman 2000). The objective of this study was to examine the spatial extent of transported materials and impacts on forest soil and vegetative communities immediately surrounding roadways based on road types classified as “Highway,” “Two-Lane Paved,” and “Gravel.” This research was located within two watersheds in the state of Vermont, in areas where a substantial area of forest existed adjacent the roadway. Using GIS mapping, transects were constructed at right angles to the road, and samples were gathered at the Shoulder, Ditch, Backslope, 10m from the edge of the forest, and 50m from road center during the summer of May 2009 to August 2009. Soil samples were analyzed for a suite of nutrients and physical characteristics, as well as heavy metals. The forest composition and percent area coverage by species of herbaceous flora and woody shrubs were also recorded. The main effects from roads were dependent on the extent of clearing and topography modification required for a roadway. The spatial extent of these modifications was correlated positively with road use intensity. Highways have the greatest ecological impact and gravel roads the least impact. The cleared area defines how much sunlight is available to plant communities and the distance that road pollutants will travel. Some heavy metals (such as Pb, Cd, Ni and Zn) were correlated positively with road use intensity. Gravel roads have higher calcium content in nearby soil when compared to other road types. This is most likely due to mobilized dust from the road base. Proximity to all road types had neutralizing effects on the soil pH relative to the acidic native forest soil. Changes in microtopography next to the road have marked effects on the composition of plant communities through maintenance and direction of water flow. Ditch areas support wetland plants, and have greater soil moisture and sulfur content, while plant communities closer to the road are characteristic of drier upland zones. The area past the edge of the forest does not appear to be affected chemically or physically by any of the road types, possibly due to the dense vegetation that develops outside of the right-of-way. To reduce the ecological footprint of future road development, road corridors should be narrowed, traffic consolidated to mass transit systems such as busses or railroad, and buffer zones of vegetation next to the right-ofway should be encouraged to contain the spread of pollutants.
26

Relationships between Avian Diversity and Vegetational Parameters in Forested Patches of the Tualatin Mountains, Oregon

Fugate, Jerry Sexton 27 April 1994 (has links)
The effect of contiguous forested habitat area on local avian diversity and species richness in the Tualatin Mountain area of northwestern Oregon was investigated. Observations of eight forested stands representing seven area values (1, 2, 7, 14, 18, 24 and 40 hectares) were made during the spring and summer of 1991 and 1992. The variables measured were chosen in an attempt to show possible relationships between vegetation factors, spatial patterns and bird communities. Kendall's rank correlation coefficients were used to analyze the data. Avian species richness and diversity were significantly correlated with forest stand (patch) size. The only significant correlation between avian species richness and diversity and vegetation measures was with percent shrub layer cover. It seems likely that avian diversity and richness are increased due to the presence of species that can utilize the interior and edges of forest stands along with species which depend upon true forested interior. When forested patch size drops below a critical area, the patch becomes all edge. Interior species are absent due to increased predation and the inability to compete with interior-edge species. Edge effect may be a contributing factor to variation in diversity of birds. The correlation of percent shrub layer cover with avian measures is accompanied by a correlation of percent shrub layer cover with distance from edge. This suggests further investigation is required to assess this relationship. Studies conducted in the northeastern and north central United States have shown a similar relationship between bird communities and forest patch size.
27

Comparative ecophysiology of temperate and tropical rainforest canopy trees of Australia in relation to climate variables

Cunningham, Shaun Cameron, 1971- January 2001 (has links)
Abstract not available
28

In vitro isolation and propagation of mammatoxin-resistant aspen

Wann, Steven R. 01 January 1985 (has links)
No description available.
29

Tritrophic interactions in forests direct and indirect interactions between birds, insect herbivores, and oaks /

Barber, Nicholas A. January 2009 (has links)
2 spread sheets included. Title from title page of PDF (University of Missouri--St. Louis, viewed February 8, 2010). Includes bibliographical references.
30

Global change and tropical forests : functional groups and responses of tropical trees to elevated CO

Ellis, Alexander, 1972- January 1997 (has links)
The paradox of tropical forests is that they are simultaneously the most diverse, the least understood, and the most imperiled terrestrial ecosystem in the world. Dramatic increases in the atmospheric carbon dioxide (CO$ sb2$) concentration threaten to adversely affect fundamental climatic and ecosystem processes, gradually changing many things which we do not yet understand. Although the impacts of this rise have been studied in temperate areas, little research has investigated tree responses in the tropics, especially under natural frost conditions. This thesis examines three central issues in tropical ecophysiology and global change. First, it investigates the feasibility of in-situ measurements of several physiological traits under heterogeneous environmental conditions in a Panamanian rainforest. Second, it studies whether physiological traits differ among species and which traits are most consistent with ecological niche. Finally, it explores how variable species are in response to elevated CO$ sb2$. If ecologically-defined functional groups were to remain physiologically similar under increased CO$ sb2$, they could be used in accurately representing the variation at the species level in a global change model of system-level responses. (Abstract shortened by UMI.)

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