Spelling suggestions: "subject:"horticulture"" "subject:"horticultures""
681 |
Breeding systems and reproduction of indigenous shrubs in fragmented ecosystems : Breeding systems and reproduction of indigenous shrubs in fragmented ecosystems :|ba thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Ecology at Massey University, Palmerston North, New ZealandMerrett, Merilyn F. January 2006 (has links)
Sixteen native shrub species with various breeding systems and pollination syndromes were investigated in geographically separated populations to determine breeding systems, reproductive success, population structure, and habitat characteristics. Of the sixteen species, seven are hermaphroditic, seven dioecious, and two gynodioecious. Two of the dioecious species are cryptically dioecious, producing what appear to be perfect, hermaphroditic flowers, but that function as either male or female. One of the study species, Raukaua anomalus, was thought to be dioecious, but proved to be hermaphroditic. Teucridium parvifolium, was thought to be hermaphroditic, but some populations are gynodioecious. There was variation in self-compatibility among the four Alseuosmia species; two are self-compatible and two are self-incompatible. Self-incompatibility was consistent amongst individuals only in A. quercifolia at both study sites, whereas individuals in A. macrophylla ranged from highly self-incompatible to self-compatible amongst four study sites. The remainder of the hermaphroditic study species are self-compatible. Five of the species appear to have dual pollination syndromes, e.g., bird-moth, wind-insect, wind-animal. High levels of pollen limitation were identified in three species at four of the 34 study sites. Moderate to high levels of pollen limitation were evident in 50% of the gender dimorphic populations compared with 31% of hermaphroditic populations. Melicope simplex populations were female-biased in 14 study plots and successful fruit set was influenced by combinations of male plant density, male flower numbers and distance to the nearest pollen. Natural fruit set in wind-pollinated species was generally higher than in animal-pollinated taxa. Populations of Coprosma spathulata were mostly malebiased, and male plant density and proximity influenced natural fruit set, with a correlation between low fruit set and low male density. Population recruitment was evident in 32 of the 34 sites. In Pimelea arenaria, recruitment failure was widespread in populations throughout the North Island despite high seed set. Gender ratios showed variation from north to south, with a lower proportion of females with increasing latitude. Many of the sixteen shrubs in this study show remarkable resilience to the effects of fragmentation of natural ecosystems, and many of the species have benefited from the creation of new edge habitat after perturbation - it may be that edges are important refugia for some native taxa, especially shrubs.
|
682 |
Characterization of ACC oxidase during leaf ontogeny in white clover (Trifolium repens L.) and Trifolium occidentale : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New ZealandDu, Zhen-Ning January 2004 (has links)
To produce plant material for this thesis, Trifolium repens (white clover) (genotype 10F) and Trifolium occidentale (genotype 18Z) were propagated to produce individual stolons trained over a plastic matrix to inhibit nodal root formation. These stolons comprised leaf tissue representative of all developmental stages, from leaf initiation, maturation through to senescence. The developmental pattern for both species in terms of leaf ontogeny was generally reproducible between vegetatively propagated clones. Three distinct 1-aminocyclopropane-1-carboxylatc (ACC) oxidase genes expressed during leaf ontogeny in white clover (Trifolium repens L.) have been identified (Hunter et al., 1999). Of the three ACC oxidase genes identified, one designated TR-ACO2 is expressed in newly initiated and mature green leaves while TR-ACO3 is expressed predominantly in the senescent leaf tissue. In order to further characterize the protein products of these genes, a series of FPLC columns was used to partially purify isoforms of ACC oxidase from leaf tissue of white clover at different developmental stages, followed by 2D gel electrophoresis to obtain further purification. Two distinct isoforms of ACC oxidase were identified and partially purified from newly initiated green (designated the NIGI isoform) and senescent (designated the SEI isoform) leaf tissue. Both purified NIGI and SEI proteins were recognized by western analysis using an anti-(Trifolium repens) TR-ACO2 antibody after SDS-PAGE or 2D gel electrophoresis. To determine whether NIGI is coded for by TR-ACO2 and SEI is coded for by gene TR-ACO3, protein spots (after 2D gel electrophoresis) were digested with trypsin and the masses of the peptide determined by matrix-assisted laser desorption ionization-timc of flight (MALDI-TOF) mass spectrometric analysis. For NIGI, the coverage of the putative protein sequence (TR-ACO2) by tryptic digestion ranged from 24.5% to 37.6%, while the observed pI (5.1) and molecular mass (37 kDa) were close to the theoretical pI (5.3) and computed mass (35.7 kDa). For SEI, the percentage coverage of the putative protein sequence (TR-ACO3) from the peptides identified ranged from 13.4% to 18.0%, while the observed pI (5.2) and molecular masses (35.0-35.5 kDa) were also close to the theoretical pI (5.5) and computed mass (35.2 kDa). These data suggest that the NIGI isoform is encoded by TR-ACO2, while the SEI isoform is encoded by TR-ACO3. ACC oxidase activity in vitro and ACC oxidase protein accumulation over 24 h in mature green leaf tissue extracts during both short and long days has been shown to be under circadian control. There are two ACC oxidase activity peaks observed, in which the pattern of fluctuation in ACC oxidase activity resulted in a high level of enzyme activity at 12:00 am (0.18-0.27 nmol ethylene/h/mg), and maximum activity at 12:00 pm (0.24-031 nmol ethylene/h/mg). Lowest activity was observed in both long and short days at 9:00 pm (0.09-0.10 nmol ethylene/h/mg). In addition, northern analysis indicated that the TR-ACO2 mRNA level also displayed a circadian pattern of expression. Investigation of the effect of protein phosphorylation and dephosphorylation on ACC oxidase activity indicated that ACC oxidase activity in vitro during the periods of maximum activity increased 36% (at 12:00 am) and 56% (at 12:00 pm) after dephosphorylation, respectively. However, there was only 21% increase in enzyme activity at the time point with lowest activity (9:00 pm) in the dephosphorylated extracts. SDS-PAGE using a mini-protein gel system or a gradient gel system showed that the molecular mass of ACC oxidase decreased after dephosphorylation when compared with phosphorylation of the enzyme. These results suggest that the phosphorylation and dephosphorylation of the ACC oxidase proteins occurs in vitro and the state does affect enzyme activity. In the second part of this thesis, the coding regions of putative ACC oxidase gene transcripts were generated from leaf tissue of genotype 18Z of T. occidentale using RT-PCR. Sequence alignments indicated that the sequences could be grouped into two distinct classes, and these coding regions were designated TO-ACO2 (Trifolium occidentale ACC oxidase 2) and TO-ACO3 (Trifolium occidentale ACC oxidase 3). TO-ACO2 and TO-ACO3 share 82% similarity in nucleotide sequence and 84% similarity in amino acid sequence. The TO-ACO2 and TO-ACO3 sequences were validated as encoding ACC oxidases by comparison with other ACC oxidases in the GenBank database and both TO-ACO2 and TO-ACO3 deduced amino acid sequences contain all the residues hitherto shown to be important for maximal activity of the enzyme. Further, TO-ACO2 had 97% identity with TR-ACO2 at the nucleotide level, and 98% identity at the amino acid level. TO-ACO3 had 97% identity with TR-ACO3 at the nucleotide level, and 96% identity at the amino acid level. Genomic Southern analysis, using 3'-UTRs of TR-ACO2 and TR-ACO3 as probes, could not confirm that TO-ACO2 and TO-ACO3 arc encoded for by distinct genes. Expression studies of TO-ACO2 and TO-ACO3 genes during leaf maturation and senescence of T. occidentale were examined using northern analysis. TO-ACO2 is expressed predominantly in newly initiated and at the onset of the mature-green leaf stage, while TO-ACO3 shows maximal expression in senescent leaf tissue. The changes of ACC oxidase activity during leaf ontogeny of T. occidentale coincided with the pattern observed for ACC oxidase protein accumulation using western analysis and image analysis.
|
683 |
Japanese Consumer Co-operatives - A Market Entry Opportunity for Queensland Fresh Horticultural ProduceAda, Richard Laird Unknown Date (has links)
It is important that Queensland horticultural producers develop export capacity. Production is increasing and Australia has a relatively small domestic market. Export also provides a means to diversify as a risk management strategy and to arrest the income decline from existing markets. This research provides Queensland horticultural producers with a practical example of how the principles of supply chain management and relationship marketing may be applied to successfully access a new export market the Japanese consumer co-operatives. The thesis examines the theories of relationship marketing and supply chain management and proposes that these constructs provide a suitable format for the development of trading relationships between Queensland producers and Japanese consumer co-operatives. Based on surveys of the co-operatives, the thesis outlines the specific philosophical and operational issues for the co-operatives which impact on their use of imported fruit and vegetables, and identifies direct supply from producers to consumers (sanchoku) as a potential strategy for gaining market entry. Key success factors are developed from the survey data and applied to a case study of a Queensland asparagus company and a mid-sized Japanese co-operative. The development of the business relationship and supply chain is chronicled for the case study firms. The dissertation concludes with observations from the case study and the co-operative survey, providing valuable insights into the strategies required by Queensland firms to build lasting relationships and profitable supply chains into Japanese consumer co-operatives.
|
684 |
Efeitos alelopáticos de microcistinas em rúcula (Eruca sativa Mill.) /Silva, Ítalo Macedo. January 2011 (has links)
Orientador: Maria do Carmo Bittencourt-Oliveira / Banca: Massanori Takaki / Banca: Ana Dionisia da Luz Coelho Novembre / Resumo: As cianotoxinas são produzidas por diversos gêneros de cianobactérias, possuem ação hepatotóxica e foram as responsáveis por vários casos de intoxicação em mamíferos. Estudos com hortaliças têm demonstrado os efeitos das microcistinas (MCs) sobre a germinação de sementes, o desenvolvimento das plântulas e o metabolismo, além do acúmulo nos tecidos foliares. O que caracteriza uma importante via de contaminação para o homem através da irrigação com água contendo cianotoxinas. Esse trabalho teve como objetivo investigar os efeitos da aplicação de extrato bruto de Microcystis aeruginosa (Kützing) Kützing, com linhagem produtora e não produtora de MCs, para a germinação de sementes, e o desenvolvimento de plântulas e plantas de rúcula, variedade Folha larga. Sementes germinadas em papel mata-borrão foram expostas a concentrações entre 0,5 a 100 μg.L-1 de MC-LR equivalente durante sete dias. Plantas cultivadas em vasos contendo substrato comercial para hortaliça foram irrigadas com solução aquosa contendo 0,5 a 10 μg.L-1 de MC-totais, ou seja, considerando todas as variantes presentes no extrato com MC. Valores de massa seca correspondentes foram empregados para o tratamento com extrato bruto sem microcistina, além de controle com água. Os resultados mostraram que MC-LR equivalente causou inibição de 30% no comprimento da parte aérea das plântulas e aumento na atividade da enzima peroxidase (POD). As concentrações aplicadas de MC-totais causaram o aumento na atividade da POD apenas para a planta jovem (folhas e raízes). Com isso, os resultados indicaram que não houve efeitos alelopáticos na germinação de sementes e na formação das plântulas, cujas sementes não foram susceptíveis aos tratamentos. O mesmo ocorreu com as plantas jovens e adultas expostas aos extratos brutos, nas concentrações testadas de MC-totais. Houve diferença no estresse ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cyanotoxins are produced by several cyanobacteria genera. They have hepatotoxic action and have been responsible for several cases of intoxication. Studies on vegetables have shown the effects of microcystins (MCs) in seed germination, seedling development and metabolism. Another concern is the crop irrigation with water containing cyanotoxins due to the possibility of toxin accumulation in leaf tissues. This characterizes an important route of contamination to humans. The aim of this study was to investigate the effects of non-purified extracts of Microcystis aeruginosa (Kützing) Kützing in the germination of seeds, development of seedlings and plants of rocket (large-leaf variety). Effects of both, toxic and non-toxic strains, were evaluated. Seeds were germinated on filter paper and than exposed to MC solution (concentrations ranging from 0,5 to 100,0 μg.L-1 of MC-LR equivalent) during seven days. Plants growing in commercial substrate for vegetable were irrigated with MC solution (concentrations ranging from 0,5 to 10,0 μg.L-1 de MC-total). Treatments containing the non-toxic strain extract (dry mass equivalent of the toxic treatment) and water (negative control) were carried out together with the toxic ones. MC-LR equivalent treatment caused inhibition of 30% in shoot length and increased activity of peroxidase (POD) in seedlings. The applied concentrations of MC-total caused increase in POD activity in young plant (leaves and roots). On the other hand, allelopathic effects were not found either on seeds germination or seedling development. Also, no allelopathic effects were found in the juvenile and adult plants exposed to extracts with any of the MC-total concentrations. Young and adult plants had different oxidative stress responses when exposed to extracts of the MCs-producing strain. Therefore, future studies should be conducted with individuals at the young stages of ... (Complete abstract click electronic access below) / Mestre
|
685 |
Fluxo de conhecimento na interação universidade-empresa : uma análise de setores tradicionais e de alta tecnologia no Brasil e na HolandaDalmarco, Gustavo January 2012 (has links)
O presente estudo tem por objetivo caracterizar o fluxo de conhecimento na interação universidade-empresa, identificando a relação em diferentes setores de diferentes países. O conceito de fluxo de conhecimento é apresentado como um complemento às teorias atuais de interação universidade-empresa, descritas principalmente pelo Triângulo de Sábato e pela Hélice Tripla. Argumenta-se que a interação universidade-empresa vem sendo apresentada pelo papel dos atores e canais de transferência de conhecimento, mas não deixa claro qual ator é responsável por iniciar a interação e o conteúdo de conhecimento transferido. Com isso, o conceito de fluxo de conhecimento é descrito pelo ator responsável por estimular a interação e pelo conteúdo de conhecimento, seja científico ou aplicado, transferido entre atores. A pesquisa foi conduzida pelo método de estudo de caso, em dois setores, horticultura e espacial, de dois países, Brasil e Holanda, totalizando 27 casos. Os resultados demonstram diferenças no fluxo de conhecimento entre os atores, relacionadas principalmente na comparação entre os países, e não tanto quanto aos setores. Os setores de horticultura e espacial holandeses possuem uma estrutura de conhecimento formada por universidades, centros tecnológicos e empresas, que desenvolvem atividades de pesquisa básica e aplicada voltadas à inovação. Como afirmam os entrevistados, comissões do governo aproximam pesquisadores e empresários, estimulando contatos informais e parcerias de desenvolvimento tecnológico. No Brasil, ambos os setores apresentam carências principalmente na geração de conhecimento, seja pesquisa básica, e na a formação de mão de obra. Os entrevistados declaram que os incentivos governamentais à pesquisa são restritos e descontínuos, dificultando o desenvolvimento tecnológico. Em relação ao fluxo de conhecimento, as interações universidade-empresa na Holanda possuem conteúdo de conhecimento descrito pelo critério pesquisa básica, pesquisa estratégica e pesquisa aplicada. No Brasil, o conteúdo de conhecimento presente no fluxo foi principalmente baseado no critério pesquisa aplicada, e tecnologia corrente. Os entrevistados de ambos os países mencionam que o estímulo ao fluxo ocorre principalmente pelo contato de empresas ou universidades, enquanto o estímulo do governo ocorre através de editais ou incentivos à pesquisa. Conclui-se que a interação universidade-empresa ocorre em ambos os países, porém o fluxo de conhecimento entre os atores reflete diferenças na estrutura científica e tecnológica instalada em cada país. Enquanto a Holanda desenvolve interações voltadas ao desenvolvimento tecnológico, no Brasil as interações buscam principalmente solucionar problemas técnicos, ou atividades de pesquisa aplicada às necessidades das empresas. Esta diferença ocorre pela reduzida capacidade científica das universidades brasileiras, pois as empresas buscam inovações em universidades e centros tecnológicos do exterior, ou desenvolvem internamente. Por fim, o conceito de fluxo de conhecimento demonstra que a Holanda possui uma avançada estrutura de pesquisa, e que comissões do governo formadas por pesquisadores e empresários aproximam os atores e alinham os objetivos tecnológicos. No Brasil, o conceito do fluxo de conhecimento apresenta restrições quanto à estrutura acadêmica de ensino e pesquisa científica, além de recursos governamentais limitados. / The present research aims to characterize the knowledge flow in university-industry relations, identifying this kind of partnership in different sectors of different countries. The concept of knowledge flow aims to complement the current university-industry relations theories, mainly described by Sábato’s triangle and the triple helix. It is argued that university-industry relations are generally defined by the role of actors and the channels of knowledge transfer. However, it is not clear which actor is responsible for initiating the interaction and the content of knowledge transferred. Thus, the concept of knowledge flow is described by the actor responsible for stimulating the relationship and the content of knowledge, between science and applied, transferred between actors. The case study research was conducted in two sectors, horticulture and space, in two countries, Brazil and The Netherlands, describing 27 cases. Results showed that differences in the knowledge flow between the actors can be mainly compared between countries, rather than between sectors. Both horticulture and space sectors in The Netherlands have a knowledge environment constituted by universities, research centres and companies which develop basic and applied research activities focused on innovations. As stated by the respondents, government commissions bring researchers and companies closer, encouraging informal contacts and partnerships for technological development. On the other hand, both sectors in Brazil present deficiencies especially in knowledge creation by basic research or training students. Respondents state that government subsidies for research are limited and discontinued, restricting technological development. Regarding the knowledge flow, university industry relations in The Netherlands are mainly defined by knowledge content criteria such as basic research, strategic research or applied research. In Brazil, the content of the knowledge flow was mainly based on applied research and current technology criteria. Respondents from both countries reported that the stimulus to the knowledge flow occurs by contact from companies or universities, while government stimulus is described by research tenders or subsidies. To conclude, universityindustry relations occur in both countries, but the knowledge flow between the actors reflects differences on the science and technology structure in each country. While The Netherlands develops interactions aiming to develop new technologies, in Brazil such relations mainly seek to solve technical issues, or applied research activities guided by market needs. This difference, however, is given by the reduced scientific capacity of Brazilian universities, as companies seek for technology innovations in research centres and universities abroad, or develops internally. Finally, the concept of knowledge flow shows that The Netherlands have an advanced research structure, and government commissions formed by researchers and companies approach the actors, aligning technology goals. In Brazil, the concept of knowledge flow demonstrates restrictions mainly in the structure of academic teaching, scientific research and also in government resources.
|
686 |
Development of Complementary Fresh-Food Systems Through the Exploration and Identification of Profit-Maximizing, Supply ChainsJanuary 2017 (has links)
abstract: One of the greatest 21st century challenges is meeting the needs of a growing world population expected to increase 35% by 2050 given projected trends in diets, consumption and income. This in turn requires a 70-100% improvement on current production capability, even as the world is undergoing systemic climate pattern changes. This growth not only translates to higher demand for staple products, such as rice, wheat, and beans, but also creates demand for high-value products such as fresh fruits and vegetables (FVs), fueled by better economic conditions and a more health conscious consumer. In this case, it would seem that these trends would present opportunities for the economic development of environmentally well-suited regions to produce high-value products. Interestingly, many regions with production potential still exhibit a considerable gap between their current and ‘true’ maximum capability, especially in places where poverty is more common. Paradoxically, often high-value, horticultural products could be produced in these regions, if relatively small capital investments are made and proper marketing and distribution channels are created. The hypothesis is that small farmers within local agricultural systems are well positioned to take advantage of existing sustainable and profitable opportunities, specifically in high-value agricultural production. Unearthing these opportunities can entice investments in small farming development and help them enter the horticultural industry, thus expand the volume, variety and/or quality of products available for global consumption. In this dissertation, the objective is three-fold: (1) to demonstrate the hidden production potential that exist within local agricultural communities, (2) highlight the importance of supply chain modeling tools in the strategic design of local agricultural systems, and (3) demonstrate the application of optimization and machine learning techniques to strategize the implementation of protective agricultural technologies.
As part of this dissertation, a yield approximation method is developed and integrated with a mixed-integer program to estimate a region’s potential to produce non-perennial, vegetable items. This integration offers practical approximations that help decision-makers identify technologies needed to protect agricultural production, alter harvesting patterns to better match market behavior, and provide an analytical framework through which external investment entities can assess different production options. / Dissertation/Thesis / Doctoral Dissertation Industrial Engineering 2017
|
687 |
Silício e cobre na produção de alface em cultivo sem solo / Silicon and copper in the soilless production of lettuceNeves, Myriam Galvão 18 February 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aimed to evaluate the effect of silicon and copper concentrations in the nutrient solution for
lettuce soilless production. Four experiments were conducted at Plant Science Department of the
Federal University of Santa Maria in a closed soilless system using 3 dm3 pots with sand. Two
experiments were with silicon, from June 17 to August 11 in winter and from 26 September to 24
October, 2014, in spring. Treatments were five silicon concentrations in the nutrient solution, two
lettuce cultivars, Veneranda (crisphead) and Stella (butterhead), and foliar spaying of silicon seven
days before harvest. Silicon concentrations in the nutrient solution were 0.0; 0.7; 1.4; 2.1 and 2.8
mmol L-1 and 0.0; 1.4; 2.8; 4.2 and 5.6 mmol L-1, respectively, and 9 mg L-1 in foliar spaying. The
experimental design was a randomized factorial 5x2x2 split plot with 11 replications. Other two
experiments were conducted with copper, from 27 October to 26 November, 2014, in spring and from
May 8 to June 22, 2015, in fall, using the same cultivars. Copper concentrations in the nutrient solution
were 0.06; 0.18; 0.3; 0.42 and 0.54 mg L-1 and 0.05; 0.75; 1.25; 1.75 and 2.25 U mg L-1, respectively.
The experimental design was a randomized factorial 5x2 split plot with 11 replications. Increasing the
silicon concentration reduced growth and development of plants of both cultivars and reduced also the
post-harvest fresh weight loss on Stella plants. It was concluded that in the range of concentrations
used in present experiments any beneficial effect of silicon on lettuce production can be expected, but
it may reduce post-harvest fresh weight loss. Growth and production were reduced by copper
concentrations on both cultivars and seasons and it was concluded that concentrations higher than
0.06 mg L-1 in the root medium have to be avoided. / O trabalho teve como objetivo avaliar o efeito da concentração de silício e cobre na produção de
alface em cultivo sem solo. Quatro experimentos foram realizados no Departamento de Fitotecnia da
Universidade Federal de Santa Maria em sistema fechado de cultivo sem solo empregando vasos de
3 dm3 com areia. Dois experimentos foram realizados com silício no inverno, entre 17 de junho e 11
de agosto e entre 26 de setembro e 24 de outubro de 2014, na primavera. Os tratamentos foram
constituídos de cinco concentrações de silício na solução nutritiva, duas cultivares de alface,
Veneranda (crespa) e Stella (lisa) e pulverização foliar de silício aos sete dias antes da colheita. As
concentrações de silício na solução nutritiva foram 0,0; 0,7; 1,4; 2,1 e 2,8 mmol L-1 e 0,0; 1,4; 2,8; 4,2
e 5,6 mmol L-1, respectivamente, e de 9 mg L-1 na pulverização foliar. O delineamento experimental foi
casualizado, com parcelas subdivididas, em esquema fatorial 5x2x2, com 11 repetições. Outros dois
experimentos foram realizados com cobre, entre 27 de outubro e 26 de novembro de 2014 na
primavera e entre 8 de maio e 22 de junho de 2015 no outono, com as mesmas cultivares. As
concentrações de cobre na solução nutritiva foram de 0,06; 0,18; 0,3; 0,42 e 0,54 mg L-1 e 0,05; 0,75;
1,25; 1,75; 2,25 mg L-1, respectivamente. O delineamento experimental foi casualizado em parcelas
subdivididas e esquema fatorial 5x2, com 11 repetições. O aumento da concentração de silício
reduziu o crescimento e desenvolvimento das plantas de ambas as cultivares e reduziu também a
perda de massa fresca pós-colheita da cultivar Stella. Concluiu-se que nas concentrações testadas
não há efeito benéfico do silício na produção da alface em cultivo sem solo, apenas na redução da
massa fresca pós-colheita. As concentrações de Cu reduziram a produção em ambas as cultivares e
épocas, concluindo-se que concentrações em torno das raízes superiores a 0,05 mg L-1 devem ser
evitadas.
|
688 |
Efeitos alelopáticos de microcistinas em rúcula (Eruca sativa Mill.)Silva, Ítalo Macedo [UNESP] 25 May 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:02Z (GMT). No. of bitstreams: 0
Previous issue date: 2011-05-25Bitstream added on 2014-06-13T19:28:49Z : No. of bitstreams: 1
silva_im_me_rcla.pdf: 340011 bytes, checksum: 05cf698f37e837803ba622b1fe6bf9e7 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / As cianotoxinas são produzidas por diversos gêneros de cianobactérias, possuem ação hepatotóxica e foram as responsáveis por vários casos de intoxicação em mamíferos. Estudos com hortaliças têm demonstrado os efeitos das microcistinas (MCs) sobre a germinação de sementes, o desenvolvimento das plântulas e o metabolismo, além do acúmulo nos tecidos foliares. O que caracteriza uma importante via de contaminação para o homem através da irrigação com água contendo cianotoxinas. Esse trabalho teve como objetivo investigar os efeitos da aplicação de extrato bruto de Microcystis aeruginosa (Kützing) Kützing, com linhagem produtora e não produtora de MCs, para a germinação de sementes, e o desenvolvimento de plântulas e plantas de rúcula, variedade Folha larga. Sementes germinadas em papel mata-borrão foram expostas a concentrações entre 0,5 a 100 μg.L-1 de MC-LR equivalente durante sete dias. Plantas cultivadas em vasos contendo substrato comercial para hortaliça foram irrigadas com solução aquosa contendo 0,5 a 10 μg.L-1 de MC-totais, ou seja, considerando todas as variantes presentes no extrato com MC. Valores de massa seca correspondentes foram empregados para o tratamento com extrato bruto sem microcistina, além de controle com água. Os resultados mostraram que MC-LR equivalente causou inibição de 30% no comprimento da parte aérea das plântulas e aumento na atividade da enzima peroxidase (POD). As concentrações aplicadas de MC-totais causaram o aumento na atividade da POD apenas para a planta jovem (folhas e raízes). Com isso, os resultados indicaram que não houve efeitos alelopáticos na germinação de sementes e na formação das plântulas, cujas sementes não foram susceptíveis aos tratamentos. O mesmo ocorreu com as plantas jovens e adultas expostas aos extratos brutos, nas concentrações testadas de MC-totais. Houve diferença no estresse... / Cyanotoxins are produced by several cyanobacteria genera. They have hepatotoxic action and have been responsible for several cases of intoxication. Studies on vegetables have shown the effects of microcystins (MCs) in seed germination, seedling development and metabolism. Another concern is the crop irrigation with water containing cyanotoxins due to the possibility of toxin accumulation in leaf tissues. This characterizes an important route of contamination to humans. The aim of this study was to investigate the effects of non-purified extracts of Microcystis aeruginosa (Kützing) Kützing in the germination of seeds, development of seedlings and plants of rocket (large-leaf variety). Effects of both, toxic and non-toxic strains, were evaluated. Seeds were germinated on filter paper and than exposed to MC solution (concentrations ranging from 0,5 to 100,0 μg.L-1 of MC-LR equivalent) during seven days. Plants growing in commercial substrate for vegetable were irrigated with MC solution (concentrations ranging from 0,5 to 10,0 μg.L-1 de MC-total). Treatments containing the non-toxic strain extract (dry mass equivalent of the toxic treatment) and water (negative control) were carried out together with the toxic ones. MC-LR equivalent treatment caused inhibition of 30% in shoot length and increased activity of peroxidase (POD) in seedlings. The applied concentrations of MC-total caused increase in POD activity in young plant (leaves and roots). On the other hand, allelopathic effects were not found either on seeds germination or seedling development. Also, no allelopathic effects were found in the juvenile and adult plants exposed to extracts with any of the MC-total concentrations. Young and adult plants had different oxidative stress responses when exposed to extracts of the MCs-producing strain. Therefore, future studies should be conducted with individuals at the young stages of ... (Complete abstract click electronic access below)
|
689 |
Fluxo de conhecimento na interação universidade-empresa : uma análise de setores tradicionais e de alta tecnologia no Brasil e na HolandaDalmarco, Gustavo January 2012 (has links)
O presente estudo tem por objetivo caracterizar o fluxo de conhecimento na interação universidade-empresa, identificando a relação em diferentes setores de diferentes países. O conceito de fluxo de conhecimento é apresentado como um complemento às teorias atuais de interação universidade-empresa, descritas principalmente pelo Triângulo de Sábato e pela Hélice Tripla. Argumenta-se que a interação universidade-empresa vem sendo apresentada pelo papel dos atores e canais de transferência de conhecimento, mas não deixa claro qual ator é responsável por iniciar a interação e o conteúdo de conhecimento transferido. Com isso, o conceito de fluxo de conhecimento é descrito pelo ator responsável por estimular a interação e pelo conteúdo de conhecimento, seja científico ou aplicado, transferido entre atores. A pesquisa foi conduzida pelo método de estudo de caso, em dois setores, horticultura e espacial, de dois países, Brasil e Holanda, totalizando 27 casos. Os resultados demonstram diferenças no fluxo de conhecimento entre os atores, relacionadas principalmente na comparação entre os países, e não tanto quanto aos setores. Os setores de horticultura e espacial holandeses possuem uma estrutura de conhecimento formada por universidades, centros tecnológicos e empresas, que desenvolvem atividades de pesquisa básica e aplicada voltadas à inovação. Como afirmam os entrevistados, comissões do governo aproximam pesquisadores e empresários, estimulando contatos informais e parcerias de desenvolvimento tecnológico. No Brasil, ambos os setores apresentam carências principalmente na geração de conhecimento, seja pesquisa básica, e na a formação de mão de obra. Os entrevistados declaram que os incentivos governamentais à pesquisa são restritos e descontínuos, dificultando o desenvolvimento tecnológico. Em relação ao fluxo de conhecimento, as interações universidade-empresa na Holanda possuem conteúdo de conhecimento descrito pelo critério pesquisa básica, pesquisa estratégica e pesquisa aplicada. No Brasil, o conteúdo de conhecimento presente no fluxo foi principalmente baseado no critério pesquisa aplicada, e tecnologia corrente. Os entrevistados de ambos os países mencionam que o estímulo ao fluxo ocorre principalmente pelo contato de empresas ou universidades, enquanto o estímulo do governo ocorre através de editais ou incentivos à pesquisa. Conclui-se que a interação universidade-empresa ocorre em ambos os países, porém o fluxo de conhecimento entre os atores reflete diferenças na estrutura científica e tecnológica instalada em cada país. Enquanto a Holanda desenvolve interações voltadas ao desenvolvimento tecnológico, no Brasil as interações buscam principalmente solucionar problemas técnicos, ou atividades de pesquisa aplicada às necessidades das empresas. Esta diferença ocorre pela reduzida capacidade científica das universidades brasileiras, pois as empresas buscam inovações em universidades e centros tecnológicos do exterior, ou desenvolvem internamente. Por fim, o conceito de fluxo de conhecimento demonstra que a Holanda possui uma avançada estrutura de pesquisa, e que comissões do governo formadas por pesquisadores e empresários aproximam os atores e alinham os objetivos tecnológicos. No Brasil, o conceito do fluxo de conhecimento apresenta restrições quanto à estrutura acadêmica de ensino e pesquisa científica, além de recursos governamentais limitados. / The present research aims to characterize the knowledge flow in university-industry relations, identifying this kind of partnership in different sectors of different countries. The concept of knowledge flow aims to complement the current university-industry relations theories, mainly described by Sábato’s triangle and the triple helix. It is argued that university-industry relations are generally defined by the role of actors and the channels of knowledge transfer. However, it is not clear which actor is responsible for initiating the interaction and the content of knowledge transferred. Thus, the concept of knowledge flow is described by the actor responsible for stimulating the relationship and the content of knowledge, between science and applied, transferred between actors. The case study research was conducted in two sectors, horticulture and space, in two countries, Brazil and The Netherlands, describing 27 cases. Results showed that differences in the knowledge flow between the actors can be mainly compared between countries, rather than between sectors. Both horticulture and space sectors in The Netherlands have a knowledge environment constituted by universities, research centres and companies which develop basic and applied research activities focused on innovations. As stated by the respondents, government commissions bring researchers and companies closer, encouraging informal contacts and partnerships for technological development. On the other hand, both sectors in Brazil present deficiencies especially in knowledge creation by basic research or training students. Respondents state that government subsidies for research are limited and discontinued, restricting technological development. Regarding the knowledge flow, university industry relations in The Netherlands are mainly defined by knowledge content criteria such as basic research, strategic research or applied research. In Brazil, the content of the knowledge flow was mainly based on applied research and current technology criteria. Respondents from both countries reported that the stimulus to the knowledge flow occurs by contact from companies or universities, while government stimulus is described by research tenders or subsidies. To conclude, universityindustry relations occur in both countries, but the knowledge flow between the actors reflects differences on the science and technology structure in each country. While The Netherlands develops interactions aiming to develop new technologies, in Brazil such relations mainly seek to solve technical issues, or applied research activities guided by market needs. This difference, however, is given by the reduced scientific capacity of Brazilian universities, as companies seek for technology innovations in research centres and universities abroad, or develops internally. Finally, the concept of knowledge flow shows that The Netherlands have an advanced research structure, and government commissions formed by researchers and companies approach the actors, aligning technology goals. In Brazil, the concept of knowledge flow demonstrates restrictions mainly in the structure of academic teaching, scientific research and also in government resources.
|
690 |
Nitrogênio no crescimento e produtividade de plantas de alface cultivadas em confinamento radicular / Nitrogen on growth and yield of lettuce plants grown under root confinementCardoso, Francieli Lima 28 August 2012 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objective of this research was to test the hypothesis that under confinement of
roots in a limited volume, the negative effects on growth and yield of lettuce plants can be
compensated by increasing the availability of N in the root media. The experiment was
conducted between Augut 11th and September 23th 2011. Lettuce transplants, cv. Stella,
bearing five leaves were planted in pots using sand as substrate. Treatments were three root
confinement levels and five N concentrations in the nutrient solution, in a 3 x 5 factorial
randomized experimental design. Root confinements were simulated by pots sizes of 2.5 dm³
(no confinement, the control); 1.0 dm³ (moderate) and 0.4 dm³ (severe). Nitrogen
concentrations were: 5.55 (T1), 8.05 (T2), 10.55 (T3), 13.05 (T4) and 15.55 (T5) mmol L-1.
There were interactions among treatments and plants grown under severe root confinement
supplied by the nutrient solution at the N concentration of 10.55 mmol L-1 N reached similar
leaf growth than those under no root confinement at 5.55mmol L-1 N. Increasing the N
concentration in the nutrient solution enhanced shoot growth but decreased root growth. The
severe root confinement did not affect root growth but reduced shoot growth. It was
concluded that shoot growth of plants under root confinement is only partially compensate by
increasing the availability of N in the root media. / A pesquisa teve por objetivo testar a hipótese de que sob condições de confinamento
das raízes em um volume limitado, os efeitos negativos no crescimento e produtividade da
planta de alface podem ser compensados aumentando a disponibilidade de N no meio
radicular. O experimento foi realizado entre 11 de agosto e 23 de setembro de 2011. Mudas de
alface da cultivar Stella com cinco folhas foram plantadas em vasos empregando areia como
substrato. Os tratamentos foram constituídos por três níveis de confinamento do sistema
radicular e cinco concentrações de nitrogênio na solução nutritiva, em esquema fatorial 3 x 5.
O confinamento das raízes foi simulado usando tamanhos de vasos de 2,5 dm3 (sem
confinamento, controle); 1,0 dm3 (moderado) e 0,4 dm3 (severo). As concentrações de
nitrogênio foram fornecidas através de uma solução nutritiva, onde as concentrações totais de
nitrogênio foram: 5,55 (T1), 8,05 (T2), 10,55(T3), 13,05 (T4) e 15,55 (T5) mmol L-1. Houve
interação entre os dois fatores, de forma que plantas sob confinamento severo das raízes na
concentração de 10,55mmol L-1 de N apresentaram crescimento de folhas similar àquelas sem
confinamento (controle) na dose de 5,55mmol L-1 de N. O aumento da concentração de N
favoreceu o crescimento da parte aérea da planta, porém, reduziu o crescimento das raízes. O
confinamento severo não afetou o crescimento das raízes porem reduziu o crescimento da
parte aérea das plantas. Concluiu-se que o crescimento da parte aérea das plantas em
confinamento radicular é compensado apenas parcialmente pelo aumento da disponibilidade de N no meio radicular.
|
Page generated in 0.0887 seconds