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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

Effects of Horticultural Oils on Photosynthesis, Fruit Maturity, and Yield of Wine Grapes

Finger, Sarah Adine 26 May 2000 (has links)
In field experiments conducted in northern Virginia during 1998, oils reduced photosynthesis, fruit maturity, and crop yield. Three applications of a 1.5% (v/v) oil/water emulsion were made to Chardonnay and Cabernet Sauvignon vine canopies at 6200 L/ha (Chardonnay) and 2440 L/ha (Cabernet Sauvignon). Net assimilation rate (NAR), soluble solids concentration (SSC), and berry size were reduced by oil treatments when compared to an untreated control. Also in 1998, a 1.5% (v/v) oil/water emulsion at 5550 L/ha and 4680 L/ha was applied to 23 wine grape cultivars. Eleven cultivars had significant foliar injury but injury was not related to reductions in fruit maturity. Experiments conducted in 1999 determined if reduced spray volumes or applications to only the fruit zone minimize reductions in NAR and SSC. Chardonnay and Cabernet Sauvignon were treated with JMS Stylet oil (1.5%) using 5600 L/ha or 1870 L/ha applied to the whole canopy or 930 L/ha applied to the fruit zone. The NAR of 5600 L/ha treated Cabernet Sauvignon was significantly lower than the NAR of control and other oil treatments on three measurement dates. The NAR of Chardonnay in the 5600 L/ha treatment was significantly lower than the NAR of control treatments in three measurements. Cabernet Sauvignon SSC was reduced by the 5600 L/ha and 1870 L/ha treatments, relative to the water treated control, on three sample dates but not at harvest. The SSC of Chardonnay in the 5600 L/ha treatment was reduced at harvest as compared to all other treatments. The SSC of Chardonnay in the 1870 and 930 L/ha treatments was reduced relative to the water control. Low volumes of oil caused less reduction in NAR and SSC; however, there are concerns about the efficacy of oils used at low volumes due to poor coverage. / Master of Science
2

Effects of Blue and Green Light on Plant Growth and Development at Low and High Photosynthetic Photon Flux

Snowden, Michael Chase 01 May 2015 (has links)
The optimal combination of wavelengths of light (spectral quality) for single leaf photosynthesis has been well characterized, but spectral quality is not well characterized in whole plants in long-term studies. Here we report the effects of eight light spectra at two photosynthetic photon fluxes (200 and 500 µmol m-2 s-1) on dry mass, leaf area index and net assimilation of seven species in replicate 21-day studies. The combination of treatments allowed us to separately assess the effects of blue and green light fraction among species and PPF. At a PPF of 500, increasing blue light from 11 to 28 % significantly decreased dry mass in tomato, cucumber, and pepper, but there was no significant effect on soybean, lettuce and wheat. At a PPF of 200, dry mass significantly decreased only in tomato across the blue light range. Effects on leaf area paralleled effects on dry mass in all species at both PPFs, indicating that the effects of blue light on dry mass were mediated by changes in leaf area. Contrary to predictions of net assimilation based on blue light response of single leaves, there was no evidence of decreasing net assimilation with increasing blue light. In contrast to the significant effect of blue light dry mass and leaf area, increasing green light fraction from zero to 30 % resulted in few significant differences. Contrary to several reports on significant green light effects on growth (both increases and decreases), we found no consistent effect of green light among species on growth, leaf area or net assimilation. Collectively, these results indicate significant differences among species in sensitivity to blue light and less sensitivity to green light, and that the effect of blue light on dry mass is primarily determined by changes in leaf area.
3

Estudo comparativo do crescimento de plantulas e de atributos foliares em especies do cerrado e da mata atlantica / Comparative study of seedling growth and leaf traits in species from cerrado and atlantic rainforest

Scarpa, Fabiano Micheletto 31 January 2007 (has links)
Orientadores: Ivany Ferraz Marques Valio, Sandra Maria Carmello-Guerreiro / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T15:55:54Z (GMT). No. of bitstreams: 1 Scarpa_FabianoMicheletto_D.pdf: 3535805 bytes, checksum: 848a8f1513a88f057d84df520b2f7e99 (MD5) Previous issue date: 2007 / Resumo: O Cerrado e a Mata Atlântica são ambientes contrastantes em relação aos fatores hídrico, nutricional e luminoso. Portanto, algumas características adaptativas são esperadas em termos do crescimento das plântulas e da morfologia e anatomia das folhas para cada ambiente. Neste trabalho, foi feito um estudo comparativo entre espécies do cerrado e da Mata Atlântica utilizando-se pares congenéricos, sendo cada par formado por uma espécie da Mata Atlântica e uma espécie do Cerrado. Estudou-se o crescimento de plântulas em 10 pares congenéricos pertencentes a 8 famílias, a morfologia funcional de folhas de indivíduos adultos em 14 pares pertencentes a 11 famílias e a anatomia foliar em 8 pares pertencentes a 7 famílias. Para os estudos de crescimento, foram avaliados os atributos: área foliar específica (AFE), razão de área foliar (RAF), razão de massa da raiz (RMR), razão de massa do caule (RMC), razão de massa das folhas (RMF), razão raiz/parte aérea (R/PA), taxa de crescimento relativo (TCR) e taxa de assimilação líquida (TAL). Para o estudo do efeito do estresse de luz no crescimento das plântulas, foi utilizado um par congenérico de espécies: Eriotheca candolleana (da mata atlântica) e Eriotheca gracilipes (do Cerrado). Foram utilizados dois níveis de irradiância: 50% e 2%. Para avaliação da morfologia funcional das folhas, folhas de indivíduos adultos das diferentes espécies estudadas os atributos suculência, AFE, espessura e largura foram avaliados. Nos estudos anatômicos, as imagens dos cortes transversais da lâmina foliar foram digitalizadas e analisadas através do programa ¿image pro-plus¿. Houve convergências de adaptações aos ambientes estudados para algumas características. Maiores valores de TCR foram em geral encontrados para espécies da Mata Atlântica, assim como maiores valores de AFE e RAF, que estão intimamente associados à interceptação de luz para o crescimento. Não houve relação entre investimento radicular e o ambiente de ocorrência das espécies. Verificou-se que as espécies do Cerrado apresentaram maior suculência e menor AFE. Os dados de AFE encontrados nas folhas adultas revelaram o mesmo padrão obtido para plântulas. Os cortes anatômicos evidenciaram uma espessura maior da lâmina foliar e do mesofilo e um parênquima mais compactado, de maneira geral, para as espécies do Cerrado. A porção laminar lignificada também apresenta uma área significativamente maior em folhas de plantas do Cerrado. Folhas mais espessas e lignificadas diminuem a interceptação de luz e reduzem assim as taxas de crescimento, o que é muito vantajoso em ambientes onde os recursos hídricos e os nutrientes são limitantes / Abstract: The Cerrado and the Atlantic Rainforest are contrasting environments in terms of water, light and nutrient availability. Thus some adaptive traits for seedling growth and leaf morphology and anatomy are expected for each habitat. In this work a comparative study was performed between the Cerrado and the Atlantic rainforest species using congeneric pairs .Each pair was composed by a species from the Cerrado and a species from the Atlantic Rainforest. Seedling growth was studied in 10 pairs from 8 families, mature leaf functional morphology was studied in 14 pairs from 11 families and leaf anatomy was studied in 8 pairs from 7 families. For seedling growth studies, specific leaf area (SLA), leaf area ratio (LAR), root mass ratio (RMR), stem mass ratio (SMR), leaf mass ratio (LMR), root/shoot ratio (R/S), relative growth rate (RGR) and net assimilation rate (NAR) were calculated. For the study of light stress effect on seedling growth it was used a congeneric pair of species: Eriotheca candolleana (from the Atlantic Rainforest) and Eriotheca gracilipes (from Cerrado). Two irradiance levels were performed (50% and 2%) For the evaluation of mature leaf functional morphology, succulence, SLA, leaf thickness and leaf width were measured. For the anatomy studies, images from leaf transversal cross section were digitalized and analised using the software image pro plus. There were adaptive convergences for some traits relative to the habitat. Higher RGR, SLA and LAR values were generally achieved for species from the Atlantic Rainforest. SLA and LAR are closely related to light interceptance for plant growth. It was not found an association between root investiment and species environment. It was observed that leaves of Cerrado species were more succulent and presented lower values of SLA. SLA data found in mature leaves showed the same pattern obtained for the seedlings. Cross sections of the leaves revealed higher lamina thickness and higher mesophyll thickness. A more condensed parenchyma was generally found for the Cerrado species. The lignified proportion of leaves was also higher in plants from the Cerrado. Thick and more lignified leaves decrease light interception and reduce growth rates. Such traits are of important adaptive value in environments where water and nutrients are limiting resources / Doutorado / Doutor em Biologia Vegetal
4

Características agronômicas e índices de trocas gasosas do tomateiro em função de sistemas de condução em ambiente protegido / Agronomic characteristics and gas exchange rates of tomato in function of cultivation system in a protected environment

Hachmann, Tiago Luan 26 February 2015 (has links)
Made available in DSpace on 2017-07-10T17:37:00Z (GMT). No. of bitstreams: 1 Tiago_Luan_Hachmann.pdf: 1649541 bytes, checksum: 8e937bb39bf1fdae7f31d4186d79cc60 (MD5) Previous issue date: 2015-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work was conducted in the period from April, 11th, 2014 until September, 9th, 2014 aiming studying the influence of the number of stems and the way of establishing these stems in productivity and quality characteristics of the tomato cultivars, and evaluate the daily course of gas exchange indexes of the tomato cultivars in the leaves exposed to solar radiation from the east (morning) or the west (afternoon). The experimental design used in the first experiment was a randomized block design with factorial 3 x 2 x 2, with four replications. Three numbers of stem per plant were tested (one, two and four steams) two forms of establishment (maintaining and removing the main stem) and two cultivars (Caniles and Rubi F1 hybrid). The total number of fruits, number of normal fruits, non-commercial and blossom-end rot was evaluated; percentage of unmarketable fruits and blossom end rot; average mass, longitudinal and transversal diameter of the normal fruits; fruit mass, transversal and longitudinal diameter, average fruit mass and productivity of the first four clusters; total mass of fruit and fruit normal mass; and was calculated productivity of normal fruits, non-commercial, with blossom end rot and total fruit yield. It was also evaluated pH, soluble solids, titratable acidity and soluble solids/titratable acidity ("ratio"). In the second experiment the experimental design was a randomized block design, factorial 2 x 2 x 6, with four replications. The first factor was composed of two evaluation positions in the plant (East and West), the second of two tomato cultivars (Caniles and Rubi) and finally six times evaluation throughout the day (8:00, 10:00, 12:00, 14:00, 16:00 and 18:00). It was measured the rate of CO2 net assimilation (A), leaf transpiration (E), stomatal conductance (gs), internal CO2 concentration (Ci) and leaf temperature (°C) and vapor pressure deficit. It was also calculated the water use efficiency (WUE) (A/E), intrinsic water use efficiency (WUEi) (A/gs) and the instantaneous efficiency of carboxylation (A/Ci). The conduction of plants with four steams is more favorable to productivity and the quality characteristics. The establishment of steams number keeping the main stem is best suited for providing greater productivity. The cultivar Caniles is the most suitable for driving on growing conditions, due to its higher yield and fruits with better "ratio". The values of net assimilation rate of CO2, leaf transpiration, stomatal conductance, leaf temperature, water use efficiency, intrinsic water use efficiency and instantaneous carboxylation efficiency on the east side are larger than on the west side. The cultivar Caniles has a higher net assimilation rate of CO2, leaf transpiration, leaf temperature and instantaneous carboxylation efficiency under conditions of high temperature and luminosity / Este trabalho foi conduzido no período de 11/04/2014 a 16/09/2014, tendo como objetivo estudar a influência do número de hastes e da forma de estabelecimento dessas hastes nas características produtivas e qualitativas de duas cultivares de tomateiro, e avaliar o curso diário dos índices de trocas gasosas de duas cultivares de tomateiro, em folhas expostas à radiação solar proveniente do quadrante leste (período da manhã) ou do quadrante oeste (período da tarde). O delineamento experimental utilizado no primeiro experimento foi de blocos casualizados, em esquema fatorial de 3 x 2 x 2, com quatro repetições. Foram testados três números de haste por planta (uma, duas e quatro hastes), duas formas de condução (mantendo a haste principal e retirando a haste principal) e duas cultivares (híbrido F1 Rubi e híbrido Caniles). Foi avaliado o número total de frutos, número de frutos normais, não comerciais e com podridão apical; porcentagem de frutos não comerciais e com podridão apical; massa média, diâmetro longitudinal e transversal dos frutos normais; massa de frutos, diâmetro transversal e longitudinal, massa média por fruto e produtividade dos quatro primeiros cachos; massa total de frutos e massa de frutos normais; e foi calculada a produtividade de frutos normais, não comerciais, com podridão apical e produtividade total de frutos. Também foi avaliado o pH, teor de sólidos solúveis, acidez titulável e a relação sólidos solúveis/acidez titulável ( ratio ). No segundo experimento o delineamento experimental utilizado foi de blocos ao acaso, em esquema fatorial 2 x 2 x 6, com quatro repetições. O primeiro fator foi composto de duas posições de avaliação na planta (Leste e Oeste), o segundo de duas cultivares de tomate (Caniles e Rubi) e por fim seis horários de avaliação ao longo do dia (8:00, 10:00, 12:00, 14:00, 16:00 e 18:00). Foi mensurada a taxa de assimilação líquida de CO2 (A), taxa de transpiração foliar (E), condutância estomática (gs), concentração interna de CO2 (Ci), temperatura foliar (°C) e déficit de pressão de vapor. Também foi calculada a eficiência no uso da água (WUE) (relação A/E), eficiência intrínseca no uso da água (WUEi) (relação A/gs) e a eficiência instantânea da carboxilação (A/Ci) (relação A/Ci). A condução das plantas com quatro hastes é mais favorável para a produtividade e para as características de qualidade. O estabelecimento do número de hastes mantendo a haste principal é mais adequado por proporcionar obtenção de maior produtividade. A cultivar Caniles é a mais adequada para a condução nas condições de cultivo, por apresentar maior produtividade e por apresentar frutos com maior ratio . Os valores de taxa de assimilação líquida de CO2, taxa de transpiração foliar, condutância estomática, temperatura foliar, eficiência no uso da água, eficiência intrínseca no uso da água e eficiência instantânea de carboxilação no quadrante leste são maiores que no quadrante oeste. A cultivar Caniles apresenta maior taxa de assimilação líquida de CO2, taxa de transpiração foliar, temperatura foliar e eficiência instantânea de carboxilação sob condições de temperatura e luminosidade elevadas

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