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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.
411

Identification of Ty3gypsy-like sequences in A. thaliana, L. sativa, Lycopersicon, and Z. mays

Leclerc-Potvin, Carole. January 1996 (has links)
No description available.
412

Livscykelanalys av det vertikala odlingssystemet Freja : En fallstudie i samarbete med Swegreen med fokus på att finna miljöpåverkans- hotspots

Brandel, Andrea, Borgström, Nora January 2024 (has links)
Livsmedelsindustrin är en bidragande faktor till klimatförändringarna, där innovativalösningar, såsom vertikal odling, kan appliceras för att främja en hållbar livsmedelsproduktion. Vertikala odlingssystem möjliggör urban inomhusodling,vertikalt i hyllplan, i kontrollerade miljöer med odlingskammare, belysningssystem samt vanligtvis jordfri odlingsmetod (t.ex. hydroponik), som är essentiella delar avsystemet. Temperatur, relativ fuktighet och artificiellt ljus regleras efter grödornas behov. Vid hydroponisk odling används odlingssubstrat såsom stenull istället för jord och växternas rötter är i konstant kontakt med det återcirkulerande vattnet i systemet, som förser växterna med näring. Tidigare livscykelanalyser av vertikala odlingssystem, om än ett begränsat antal, belyser elförbrukningen som den största bidragande faktorn till miljöpåverkan, samt att utbyte av olika material kan generera en lägre total miljöpåverkan. Examensarbetet syftar till att utföra en livscykelanalys på Swegreens vertikala odlingssystemet Freja, på ICA Maxi i Solna. Vidare syftar livscykelanalysen till att identifiera de faser och flöden som står för betydande miljöpåverkan, samt några förbättringsförslag. Det vertikala odlingssystemet antar perspektivet ‘vagga till användning’ under 30 år, exkluderande monterings- och sluthanteringsfasen. Användningsfasen innefattar sallatens livscykel från ‘vagga till grav’, exkluderande förtäringsfasen. Den funktionella enheten är 1 kg producerad ekbladssallat tillgänglig för konsumenter av klass 1. Data har inhämtats från både Swegreens digitaliserade data och från en tidigare studie utförd på Swegreens odlingssystem Saga. För bearbetning har programvaran SimaPro och databasen Ecoinvent 3.8 använts. Resultaten analyseras utifrån miljöpåverkanskategorierna ekotoxicitet (sötvatten), fossil resursanvändning, försurning, klimatförändringar, markanvändning, resursanvändning (mineraler och metaller), vattenanvändning och övergödning (sötvatten). Odlingsfasen för sallaten (innehållande elanvändning) är systemets främsta hotspot, följt av råmaterialsfasen för sallat, som orsakar störst miljöpåverkan för samtliga miljöpåverkanskategorier, förutom för resursanvändning (mineraler och metaller). Resultaten kan ej generaliseras eftersom de beror på val av funktionell enhet, systemgränser samt typ av data. Resultaten från känslighetsanalysen för energiproduktion och sluthantering tyder på att olika scenarion genererar lägst miljöpåverkan, beroende på vilka miljöpåverkanskategorier som anses mest relevanta. / The food industry is a contributing factor to climate change, where innovative solutions, such as vertical farming, can be applied to promote sustainable food production. Vertical farming systems enable urban indoor farming, vertically on shelves, in controlled environments with cultivation chambers, lighting systems and usually soil-free cultivation methods (e.g. hydroponics), that are essential parts of the system. Temperature, relative humidity and artificial light are regulated to satisfy the crops needs. Hydroponic cultivation utilizes growing mediums such as rock wool instead of soil and the roots of the plants are in constant contact with the recirculating water in the system, which provides the plants with nutrients. Previous life cycle assessments of vertical farming systems, although limited in numbers,highlight the electricity consumption as the largest contributing factor to the environmental impact, as well as replacing different materials for a lower environmental impact. This study aims to assess the environmental impacts and hot spots, through the use of life cycle assessment, on Swegreen's vertical farming system Freja, at ICA Maxi Solna. Furthermore the life cycle assessment aims to identify the phases and flows that accounts for significant environmental impact, as well as some suggestions for improvement. The vertical farming system applies the perspective of ‘cradle to use’for 30 years, not including the assembly or waste disposal phase. The use phase includes the life cycle of lettuce, from ‘cradle to grave’, not including the consumption phase. The functional unit is 1 kg of produced oak leaf lettuce, class 1,available to consumers. Data has been obtained from both Swegreen's digitized data and from a previous study conducted on Swegreen's farming system Saga. To process the data, the software SimaPro and the Ecoinvent 3.8 database was applied. Results are analyzed with regards to the environmental impact categories ecotoxicity (freshwater), fossil resource use, acidification, climate change, land use,resource use (minerals and metals), water use and eutrophication (freshwater).Results indicate that the lettuce cultivation phase (containing electricity use) is the main hotspot of the system, followed by the raw material phase for the lettuce. Aphase that also dominates in all environmental impact categories, except for resource use (minerals and metals). Results cannot be generalized since they dependon the choice of functional unit, system boundaries and type of data. The sensitivity analysis regarding the energy production and waste disposal suggests that different alternatives cause the lowest environmental impact, depending on which environmental impact categories are considered the most important.
413

A plant health management system for aphididae on lettuce under variable shadehouse conditions in the central Free State, South Africa

Pretorius, Rudolph Johannes January 2008 (has links)
Thesis (M. Tech) --Central University of Technology, Free State, 2008 / Aphids (Hemiptera: Aphididae) are amongst the most destructive insects in agricultural crop production systems. This reputation stems from their complex life cycles which are mostly linked to a parthenogenetic mode of reproduction, allowing them to reach immense population sizes within a short period of time. They are also notorious as important and efficient vectors of several plant viral diseases. Their short fecund life cycles allow them to be pests on crops with a short growth period, e.g. lettuce (Lactuca sativa L.). It is common practice to provide this crop with some degree of protection from environmental extremes on the South African Highveld. Shadehouses are popular in this regard, but aphids are small enough to find their way into these structures, and their presence on lettuce is discouraged due to phytosanitary issues. In addition, the excessive use of insecticides is criticized due to the negative influence on human health, and because aphids can rapidly develop resistance. This necessitates the use of alternative control options in order to suppress aphid numbers. Biological control is popular in this regard and the use of predatory ladybirds (Coleoptera: Coccinellidae) is a popular choice. This study investigated the aphid and coccinellid species complex encountered under varying shadehouse conditions on cultivated head lettuce in the central Free State Province (South Africa). Their seasonality was also examined, along with variations in their population size throughout a one-year period. Finally, the impact of varying aphid populations on some physical characteristics of head lettuce was examined, and recommendations for aphid control (using naturally occurring coccinellid predators) were made. Two shadehouse structures were evaluated during this study. One was fully covered with shade netting and designed to exclude the pugnacious ant, Anoplolepis custodiens (Hymenoptera: Formicidae), while the other was partially covered with shade netting (on the roof area) allowing access to the ants. Six cycles of head lettuce were planted and sampled four times during each cycle. These were scheduled to monitor the seedling, vegetative and heading stage of lettuce. Four important aphid species were recorded on the lettuce, namely Acyrthosiphon lactucae, Nasonovia ribisnigri, Myzus persicae and Macrosiphum euphorbiae. Both structures harboured similar aphid and coccinellid species, but their population dynamics differed. A. lactucae dominated in the absence of A. custodiens in the fully covered structure (whole study), while N. ribisnigri dominated in the partially covered structure in the presence of these ants during the warmer months (December – January). M. euphorbiae replaced this species as the dominant species in the absence of A. custodiens (April – September). M. persicae occured during the winter (May – August) in the fully covered structure. Promising coccinellid predators were Hippodamia variegata and Scymnus sp. 1, and to a lesser extent, Exochomus flavipes and Cheilomenes lunata. However, the fully covered structure hampered the entrance of the larger adult coccinellid species, resulting in their lower occurrence. Aphid and coccinellid activity peaked during the summer months (October – January), and the fully covered structure attained the highest aphid infestation levels and coccinellid larval numbers during this time. On the other hand, aphid numbers were higher in the partially covered structure during the cooler months of the year (April – July) and this structure also harboured more adult coccinellids. In most cases, aphid infestation levels did not affect the amount of leaves formed. However, symptomatic damage in terms of head weight reduction did occur under severe infestation levels. Specific environmental conditions within a shadehouse structure concurrently contributed to this reduction, with less favourable conditions accelerating this condition. Results from this study have shown that even though the type of shadehouse structure does not influence the insect species complex found on lettuce, it does have an influence on detrimental and beneficial insect population dynamics. Aphid species infesting lettuce have been identified, along with coccinellid predators that could potentially be used in their control. Both types of structures had advantages and disadvantages, and therefore, decisions concerning shadehouses should not be focused on which type of structure to use, but rather which type of structure to use during different seasons of the year.
414

Interações do Lettuce mosaic vírus (LMV) x afídeos vetores nas regiões produtoras de alface (Lactuca sativa L.) do cinturão verde de São Paulo

Chaves, Alexandre Levi Rodrigues [UNESP] 24 May 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-05-24Bitstream added on 2014-06-13T18:45:55Z : No. of bitstreams: 1 chaves_alr_dr_botfca.pdf: 1845018 bytes, checksum: 6e354e18d8a7d6379c01e67c86d71ad8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Secretaria Agricultura / A alface é uma das hortaliças de maior importância no Brasil e o estado de São Paulo destaca-se como sendo o maior produtor, gerando uma renda anual de cerca de 40 milhões de reais. Como a virose causada pelo Lettuce mosaic vírus (LMV) é uma das principais doenças da cultura, o presente estudo teve como objetivo avaliar a diversidade, a dinâmica populacional e o papel dos afídeos na disseminação do LMV, em três áreas recentemente destinadas à produção intensiva de alface. Assim, os campos de produção situados nos municípios de Igaratá, Jacareí e Jarinu, foram monitorados durante 12 meses. Foram utilizadas três tipos de armadilhas: adesivas amarelas, para determinar a densidade populacional dos afídeos; de Moericke que proporcionaram a determinação das espécies que apresentavam hábito migratório; e as de azulejo verde Irwin que, sendo mais seletivas, determinaram a atividade de vôo das espécies envolvidas na disseminação do LMV. Constatou-se nas 3 regiões, a predominância de dez espécies de afideos. Dentre as de hábito polífago, destacaram-se as espécies Aphis gossypii, A. fabae, Aulacorthum solani, Macrosiphum euphorbiae e Myzus persicae; já as de hábito oligófago, foram capturadas Hyperomyzus lactucae, Nasonovia ribisnigri, Pemphigius bursarius e Uroleucom ambrosiae. Acyrthosiphon lactucae foi a única espécie monófaga. As amostras de alface foram também coletadas e submetidas a testes sorológicos. Constatou-se, que a incidência do LMV na cultura - 2 - da alface estava relacionada não somente aos picos de vôo das espécies de afídeos, mas também às variedades tolerantes e suscetíveis de alface introduzidas no campo. Observou-se também que a temperatura atuou diretamente na densidade populacional dos afídeos e, conseqüentemente, interferiu na incidência do LMV no campo. A atividade de vôo dos afídeos foi menor durante... . / Lettuce is one of the most important vegetables in Brazil, and the State of São Paulo is the major producer, with an annual revenue of about R$ 40 millions. Since viruses can be limiting factors to this production, the present study was designed to evaluate the diversity and dynamic population of aphids, as well as the role of this vector in the spread of LMV. For this, three regions where intensive production of lettuce was recently introduced in Igaratá, Jacareí and Jarinu were monitored for 12 months. The aphids were caught using yellow adhesive traps for determining the aphid population diversity; Moerick traps were used to evaluate the aphid species with migratory habits; while green tile traps (Irvin), which are more selective, were used to estimate flight activity of species involved in spread of LMV. The predominance of 10 aphid species was observed in the 3 evaluated areas. Among them, Aphis gossypii, A. fabae, Aulacorthum solani, Macrisiphum euphorbiae and Myzus persicae stood out as species with polyphagous habits. Hyperomyzus lactucae, Nasonovia ribisnigri, Pemphigius bursarius and Uroleucom ambrosiae, with olyphagous habits, were also collected. With monophagous habits only Acyrthosiphon lactucae was caught. The lettuce samples were also collected and submitted to serological tests. It was observed that the incidence of LMV in lettuce crops was related not only to the peaks of the aphid flight activity but also to the tolerant and susceptible lettuce varieties introduced to the crop. The temperature acted on the population diversity of the aphids and, consequently, influenced the incidence of LMV. The flight activity of aphids was smaller during the winter, and LMV detection followed this trend even when susceptible varieties were introduced. However, during the other seasons these results were not observed, and the tolerance of the cultivar Elisa... (Complete abstract, click electronic address below).
415

Avaliação da contaminação de alface (Lactuca sativa) por coliformes termotolerantes e Escherichia coli em sistemas de cultivo orgânico e convencional

Lotto, Mariana de Castro 15 December 2008 (has links)
Made available in DSpace on 2016-06-02T18:57:20Z (GMT). No. of bitstreams: 1 2330.pdf: 2747102 bytes, checksum: 42b3374c620038a839a3f3c1d80f9df0 (MD5) Previous issue date: 2008-12-15 / Financiadora de Estudos e Projetos / Lettuce (Lactuca sativa) is the most consumed vegetable in Brazil, being classified as an important food, to be a rich source of vitamins. According to the practices adopted, its cultivation can be organic or conventional. However, lettuce can be a transmitter of pathogenic microorganisms to humans, as thermotolerant coliforms and Escherichia coli, since it is in contact with these contaminants often present in soil, water, in natural inputs (poultry litter) providing their development and survival. This research aimed to assess quantitatively the presence of thermotolerant coliforms and E. coli in water for irrigation and washing water, and the not washed and washed lettuce, grown under organic and conventional systems. The samples were collected in ten farms, five under organic and five under conventional systems, located at the cities of Ibiúna, Jaguariúna, Campinas e Morungaba - SP. In the laboratory, the samples were submitted to the analysis by the technique of counting the Most Probable Number. The results show that water for irrigation was considered one of the main factors responsible for contamination of lettuce, as showed by the presence ofhigh rate of thermotolerant coliforms and E. coli, independent of the cultivation system. However, the conventional system had been showing levels of contamination by thermotolerant coliforms and E. coli in water higher thanin organic system. In lettuce, pre washing contributed to the reduction of contamination by thermotolerant coliforms and E. coli in the product; however contamination by thermotolerant coliforms was considered high in the both cultivation systems. Moreover, others practices used in the farm such as personal hygiene, the inappropriate use of compost and the presence of animals in the areas of crops are source of contamination. / A alface (Lactuca sativa) é a hortaliça folhosa mais consumida no Brasil, sendo classificada como um importante alimento para a população por ser uma rica fonte de vitaminas. Em função das práticas adotadas, o seu cultivo pode ser orgânico ou convencional. No entanto, alface pode ser um veículo transmissor de microrganismos patogênicos ao homem, como coliformes termotolerantes e Escherichia coli, uma vez que se encontra em contato com esses contaminantes presentes freqüentemente no solo, na água, nos insumos naturais (cama de frango) propiciando o desenvolvimento e a sobrevivência dos mesmos. O objetivo deste trabalho foi avaliar, quantitativamente, a presença de coliformes termotolerantes e de E.coli em água de irrigação e de pré-lavagem, assim como, o produto alface não lavada e pré-lavada, cultivada sob cultivo orgânico e convencional, em relação à recomendação da ANVISA. As coletas foram realizadas em dez propriedades, cinco de cultivo orgânico e cinco de cultivo convencional, localizadas nas cidades de Ibiúna, Jaguariúna, Campinas e Morungaba - SP. Em laboratório, as amostras foram submetidas à análise de tubos múltiplos e série bioquímica e procedeu-se a avaliação pela técnica de contagem do Número Mais Provável. Os resultados mostraram um alto índice de coliformes termotolerantes e E. coli na água de irrigação, sendo um fator importante pela contaminação da alface, independente do sistema de cultivo. Todavia, o cultivo convencional apresentou índices de contaminação por esses microrganismos na água superiores ao do cultivo orgânico. No produto alface, a pré-lavagem contribuiu para a redução da contaminação por coliformes termotolerantes e E. coli, entretanto a contaminação pelo primeiro foi mais alta em ambos os sistemas de cultivos. Além disso, outras práticas utilizadas nas propriedades como a higiene pessoal, o uso de adubos compostados inadequados e a presença de animais nas áreas de cultivo são fontes de contaminação.
416

Avaliação da contaminação de alface (Lactuca sativa) por coliformes termotolerantes e Escherichia coli em sistemas de cultivo orgânico e convencional

Lotto, Mariana de Castro 15 December 2008 (has links)
Made available in DSpace on 2016-06-02T18:57:27Z (GMT). No. of bitstreams: 1 2330.pdf: 2747102 bytes, checksum: 42b3374c620038a839a3f3c1d80f9df0 (MD5) Previous issue date: 2008-12-15 / Financiadora de Estudos e Projetos / Lettuce (Lactuca sativa) is the most consumed vegetable in Brazil, being classified as an important food, to be a rich source of vitamins. According to the practices adopted, its cultivation can be organic or conventional. However, lettuce can be a transmitter of pathogenic microorganisms to humans, as thermotolerant coliforms and Escherichia coli, since it is in contact with these contaminants often present in soil, water, in natural inputs (poultry litter) providing their development and survival. This research aimed to assess quantitatively the presence of thermotolerant coliforms and E. coli in water for irrigation and washing water, and the not washed and washed lettuce, grown under organic and conventional systems. The samples were collected in ten farms, five under organic and five under conventional systems, located at the cities of Ibiúna, Jaguariúna, Campinas e Morungaba - SP. In the laboratory, the samples were submitted to the analysis by the technique of counting the Most Probable Number. The results show that water for irrigation was considered one of the main factors responsible for contamination of lettuce, as showed by the presence ofhigh rate of thermotolerant coliforms and E. coli, independent of the cultivation system. However, the conventional system had been showing levels of contamination by thermotolerant coliforms and E. coli in water higher thanin organic system. In lettuce, pre washing contributed to the reduction of contamination by thermotolerant coliforms and E. coli in the product; however contamination by thermotolerant coliforms was considered high in the both cultivation systems. Moreover, others practices used in the farm such as personal hygiene, the inappropriate use of compost and the presence of animals in the areas of crops are source of contamination. / A alface (Lactuca sativa) é a hortaliça folhosa mais consumida no Brasil, sendo classificada como um importante alimento para a população por ser uma rica fonte de vitaminas. Em função das práticas adotadas, o seu cultivo pode ser orgânico ou convencional. No entanto, alface pode ser um veículo transmissor de microrganismos patogênicos ao homem, como coliformes termotolerantes e Escherichia coli, uma vez que se encontra em contato com esses contaminantes presentes freqüentemente no solo, na água, nos insumos naturais (cama de frango) propiciando o desenvolvimento e a sobrevivência dos mesmos. O objetivo deste trabalho foi avaliar, quantitativamente, a presença de coliformes termotolerantes e de E.coli em água de irrigação e de pré-lavagem, assim como, o produto alface não lavada e pré-lavada, cultivada sob cultivo orgânico e convencional, em relação à recomendação da ANVISA. As coletas foram realizadas em dez propriedades, cinco de cultivo orgânico e cinco de cultivo convencional, localizadas nas cidades de Ibiúna, Jaguariúna, Campinas e Morungaba - SP. Em laboratório, as amostras foram submetidas à análise de tubos múltiplos e série bioquímica e procedeu-se a avaliação pela técnica de contagem do Número Mais Provável. Os resultados mostraram um alto índice de coliformes termotolerantes e E. coli na água de irrigação, sendo um fator importante pela contaminação da alface, independente do sistema de cultivo. Todavia, o cultivo convencional apresentou índices de contaminação por esses microrganismos na água superiores ao do cultivo orgânico. No produto alface, a pré-lavagem contribuiu para a redução da contaminação por coliformes termotolerantes e E. coli, entretanto a contaminação pelo primeiro foi mais alta em ambos os sistemas de cultivos. Além disso, outras práticas utilizadas nas propriedades como a higiene pessoal, o uso de adubos compostados inadequados e a presença de animais nas áreas de cultivo são fontes de contaminação.
417

Interações do Lettuce mosaic vírus (LMV) x afídeos vetores nas regiões produtoras de alface (Lactuca sativa L.) do cinturão verde de São Paulo /

Chaves, Alexandre Levi Rodrigues, 1966- January 2006 (has links)
Orientador: Marcelo Agenor Pavan / Banca: Carlos Frederico Wilcken / Banca: Addolorata Colariccio / Banca: Valdir Atsushi Yuri / Banca: José Alfredo Caran de S. Dias / Resumo: A alface é uma das hortaliças de maior importância no Brasil e o estado de São Paulo destaca-se como sendo o maior produtor, gerando uma renda anual de cerca de 40 milhões de reais. Como a virose causada pelo Lettuce mosaic vírus (LMV) é uma das principais doenças da cultura, o presente estudo teve como objetivo avaliar a diversidade, a dinâmica populacional e o papel dos afídeos na disseminação do LMV, em três áreas recentemente destinadas à produção intensiva de alface. Assim, os campos de produção situados nos municípios de Igaratá, Jacareí e Jarinu, foram monitorados durante 12 meses. Foram utilizadas três tipos de armadilhas: adesivas amarelas, para determinar a densidade populacional dos afídeos; de "Moericke" que proporcionaram a determinação das espécies que apresentavam hábito migratório; e as de azulejo verde "Irwin" que, sendo mais seletivas, determinaram a atividade de vôo das espécies envolvidas na disseminação do LMV. Constatou-se nas 3 regiões, a predominância de dez espécies de afideos. Dentre as de hábito polífago, destacaram-se as espécies Aphis gossypii, A. fabae, Aulacorthum solani, Macrosiphum euphorbiae e Myzus persicae; já as de hábito oligófago, foram capturadas Hyperomyzus lactucae, Nasonovia ribisnigri, Pemphigius bursarius e Uroleucom ambrosiae. Acyrthosiphon lactucae foi a única espécie monófaga. As amostras de alface foram também coletadas e submetidas a testes sorológicos. Constatou-se, que a incidência do LMV na cultura - 2 - da alface estava relacionada não somente aos picos de vôo das espécies de afídeos, mas também às variedades tolerantes e suscetíveis de alface introduzidas no campo. Observou-se também que a temperatura atuou diretamente na densidade populacional dos afídeos e, conseqüentemente, interferiu na incidência do LMV no campo. A atividade de vôo dos afídeos foi menor durante... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: Lettuce is one of the most important vegetables in Brazil, and the State of São Paulo is the major producer, with an annual revenue of about R$ 40 millions. Since viruses can be limiting factors to this production, the present study was designed to evaluate the diversity and dynamic population of aphids, as well as the role of this vector in the spread of LMV. For this, three regions where intensive production of lettuce was recently introduced in Igaratá, Jacareí and Jarinu were monitored for 12 months. The aphids were caught using yellow adhesive traps for determining the aphid population diversity; Moerick traps were used to evaluate the aphid species with migratory habits; while green tile traps (Irvin), which are more selective, were used to estimate flight activity of species involved in spread of LMV. The predominance of 10 aphid species was observed in the 3 evaluated areas. Among them, Aphis gossypii, A. fabae, Aulacorthum solani, Macrisiphum euphorbiae and Myzus persicae stood out as species with polyphagous habits. Hyperomyzus lactucae, Nasonovia ribisnigri, Pemphigius bursarius and Uroleucom ambrosiae, with olyphagous habits, were also collected. With monophagous habits only Acyrthosiphon lactucae was caught. The lettuce samples were also collected and submitted to serological tests. It was observed that the incidence of LMV in lettuce crops was related not only to the peaks of the aphid flight activity but also to the tolerant and susceptible lettuce varieties introduced to the crop. The temperature acted on the population diversity of the aphids and, consequently, influenced the incidence of LMV. The flight activity of aphids was smaller during the winter, and LMV detection followed this trend even when susceptible varieties were introduced. However, during the other seasons these results were not observed, and the tolerance of the cultivar Elisa... (Complete abstract, click electronic address below). / Doutor
418

ARSENIC REMOVAL BY PHYTOFILTRATION AND SILICON TREATMENT : A POTENTIAL SOLUTION FOR LOWERING ARSENIC CONCENTRATIONS IN FOOD CROPS

Sandhi, Arifin January 2017 (has links)
Use of arsenic-rich groundwater for crop irrigation can increase the arsenic (As) content in food crops and act as a carcinogen, compromising human health. Using aquatic plant based phytofiltration is a potential eco-technique for removing arsenic from water. The aquatic moss species Warnstorfia fluitans grows naturally in mining areas in northern Sweden, where high concentrations of arsenic occur in lakes and rivers. This species was selected as a model for field, climate chamber and greenhouse studies on factors governing arsenic removal and arsenic phytofiltration of irrigation water. The arsenic and silicon (Si) concentrations in soil, water and plant samples were measured by AAS (atomic absorption spectrophotometry), while arsenite and arsenate species were determined using AAS combined with high pressure liquid chromatography (HPLC) with an anion exchange column. The arsenic content in grains of hybrid and local aromatic rice (Oryza sativa) cultivars with differing arsenic accumulation factor (AF) values was investigated in an arsenic hotspot in Bangladesh. The results showed that arsenic AF was important in identifying arsenic-safer rice cultivars for growing in an arsenic hotspot. The study based on silicon effect on arsenic uptake in lettuce showed that arsenic accumulation in lettuce (Lactuca sativa) could be reduced by silicon addition. The aquatic moss had good phytofiltration capacity, with fast arsenic removal of up to 82% from a medium with low arsenic concentration (1 µM). Extraction analysis showed that inorganic arsenic species were firmly bound inside moss tissue. Absorption of arsenic was relatively higher than adsorption in the moss. Regarding effects of different abiotic factors, plants were stressed at low pH (pH 2.5) and arsenic removal rate was lower from the medium, while arsenic efflux occurred in arsenate-treated medium at low (12°C) and high (30°C) temperature regimes. Besides these factors, low oxygenation increased the efficiency of arsenic removal from the medium. Finally, combining W. fluitans as a phytofilter with a lettuce crop on a constructed wetland significantly reduced the arsenic content in edible parts (leaves) of lettuce. Thus W. fluitans has great potential for use as an arsenic phytofilter in temperate regions. / <p>QC 20170323</p>
419

Prospects for the beneficial use of arbuscular mycorrhizal fungi in horticulture in combination with organic and inorganic fertilizers

Perner, Henrike 28 November 2006 (has links)
Aufgrund seines Nährstoffaneignungsvermögens und Stimulierung des Pflanzenmetabolismus kann der Arbuskuläre Mykorrhiza (AM) Pilz im Gartenbau nutzbringend eingesetzt werden. Der Fokus der Arbeit liegt auf den Möglichkeiten des AM Pilzes a) pflanzenernährerische Probleme zu lösen, b) die Blütenbildung bei Zierpflanzen zu steigern und c) das Gesundheitspotential von Gemüse für den Menschen zu erhöhen (sekundäre Pflanzenmetaboliten). Zur Lösung pflanzenernährerischer Probleme wurden Porree, Pelargonie und Poinsettie auf Torf-Substraten mit 20% und 40% Kompostzusatz untersucht. Ferner wurde Salat auf Torf-Substrat mit drei P Behandlungen getestet: substrateigenes P, Rohphosphat und lösliches P. Frühlingszwiebeln und Schnittknoblauch wurden in Nährlösungen auf Perlit mit niedrigem, mittlerem und hohem NH4+/NO3- Verhältnis ernährt. Gemessen wurde die AM Kolonisation, die Trockenmasse und die N, P, K, S, NO3-, Mg und Zn Konzentrationen im Spross. Die Blütenbildung von Pelargonien und Poinsettien wurde auf Torf-Kompost-Substraten untersucht. Der Einfluss auf die sekundäre Metaboliten von Frühlingszwiebeln und Schnittknoblauch wurde zusammen mit drei NH4+/NO3- Verhältnissen geprüft (s.o.). Untersucht wurden Glukose, Fruktose, Saccharose, lösliche Feststoffe und organische Schwefelverbindungen (gemessen als Pyruvat). Eine AM Kolonisation konnte die Nährstoffversorgung der Pflanze verbessern und die Blütenbildung erhöhen. Jedoch profitierten die Pflanzen unter den beschriebenen experimentellen Bedingungen nicht durchgängig in ihrem Wachstum und Metaboliten vom AM Pilz. Die Zugaben von Kompost ermöglichte die Verbesserung der Substratqualität für die Nährstoffversorgung und das Pflanzenwachstum unter ökologischen Gartenbaubedingungen. Der Ertrag von gesundheitsfördernden organischen Schwefelverbindungen konnte in Abhängigkeit von der jeweiligen Allium Spezies, durch eine Variation des Ammonium/Nitrat Verhältnissen und/oder durch einen AM Effekt auf das Wachstum gesteigert werden. / Arbuscular mycorrhizal (AM) fungi can be beneficial for horticultural crops due to their nutrient acquisition properties and stimulation of the plant metabolism. The present work focuses on the prospects of AM fungi a) to solve plant nutritional problems, b) to induce flower development of ornamental plants, and c) to improve the health potential of crop plants for humans. Contribution of AM fungi to plant nutritional problems were investigated with leek, pelargonium and poinsettia plants on peat-based substrates with 20% and 40% compost additions. Moreover, lettuce plants were supplied on peat-based substrates with substrate own P, rock phosphate, or highly soluble P. Bunching onion and chinese chive were propagated on perlite in nutrient solution with low, medium and high NH4+:NO3- ratios. Mycorrhizal colonization, dry weight, and N, P, K, S, NO3-, Mg and Zn concentrations in plants were measured. Mycorrhizal effects on bud and flower development of pelargonium and poinsettia plants were investigated on peat-based compost substrates. Treatment effects on secondary metabolites in bunching onion and chinese chive were determined by exposing mycorrhizal and non mycorrhizal plants to three NH4+:NO3- supply ratios. The metabolites measured were glucose, fructose, and sucrose, total soluble solids, and organosulfur compounds (measured as pyruvic acid). Colonization improved plant nutrient status and flower development. Under the described experimental conditions, however, plants did not consistently benefit in growth or plant composition from the mycorrhizal symbiosis. Additions of compost were a means of improving the substrate quality for an increased plant nutrient acquisition and plant growth in organic horticulture. The plant quality of Allium species in respect to organosulfur compounds was increased by taking the individual Allium species into consideration, their specific requirements for an optimal NH4+:NO3- supply ratio, and a possible AM effect on plant growth.
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Viabilidade agroeconômica da alface (Lactuca sativa L.) / fertilizada com feijão mungo (Vigna radiata L.) e esterco bovino.

NEVES, Ana Paula Morais. 27 May 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-27T13:22:22Z No. of bitstreams: 1 ANA PAULA MORAIS NEVES - DISSERTAÇÃO PPGSA PROFISSIONAL 2017..pdf: 735461 bytes, checksum: c320ee1307d508a5d5811325882d133c (MD5) / Made available in DSpace on 2018-05-27T13:22:22Z (GMT). No. of bitstreams: 1 ANA PAULA MORAIS NEVES - DISSERTAÇÃO PPGSA PROFISSIONAL 2017..pdf: 735461 bytes, checksum: c320ee1307d508a5d5811325882d133c (MD5) Previous issue date: 2016-11-29 / Uso de leguminosas como adubo verde é uma prática bastante consolidada, pelo fato de estar adicionando ao solo material vegetal rico em nitrogênio. O experimento foi conduzido na Fazenda Experimental Rafael Fernandes, no distrito de Alagoinha, zona rural de Mossoró-RN no período de agosto de 2015 a janeiro de 2016, com o objetivo de avaliar a Presença e ausência do feijão mungo sob doses de esterco bovino na viabilidade agroeconômica da alface. O delineamento experimental utilizado foi de blocos completos casualizados com os tratamentos arranjados em esquema fatorial 4 x 2, com quatro repetições. O primeiro fator foi constituído das doses de esterco bovino (1,0; 2,0; 3,0; 4,0 kg m-2 de canteiro) e o segundo fator foi constituído pela presença e ausência do adubo verde (feijão mungo). A cultivar da alface utilizada foi a “Regina”. Foram avaliadas as seguintes características: altura de planta, número de folhas planta-1, diâmetro da cabeça, produção de alface e massa seca de alface. Foram determinados alguns indicadores econômicos tais como: custo de produção, renda bruta, renda líquida, taxa de retorno e índice de lucratividade dos dois cultivos. Não houve interação entre os fatores-tratamentos para as características de produção, com produção de alface de 87,8 kg/100 m2. Houve diferença estatística no fator presença e ausência do feijão mungo com valores médios de 81,4 e 67 kg/100 m2 de alface, respectivamente. A maior eficiência econômica no cultivo da alface se deu na presença do feijão mungo na quantidade de 3,0 kg m-2, com renda bruta de 3343,75, renda líquida de 1582,40, taxa de retorno de 1,90 e índice de lucratividade de 43,42%. A utilização de feijão mungo no cultivo da alface constitui-se em uma opção viável para ser utilizado pelo agricultor. / The use of legumes as green manure is a well-established practice, because it is adding nitrogen-rich plant material to the soil. The experiment was conducted at the Fazenda Experimental Rafael Fernandes, in the district of Alagoinha, rural area of Mossoró-RN, from August 2015 to January 2016, with the objective of evaluating the Presence and absence of mung bean under doses of bovine manure in the agroeconomic viability of lettuce. The experimental design was a randomized complete block with treatments arranged in a 4 x 2 factorial scheme, with four replications. The first factor consisted of bovine manure (1.0, 2.0, 3.0, 4.0 kg m-2 of bed) and the second factor was the presence and absence of green mango (mung bean). The lettuce cultivar used was the "Regina". The following characteristics were evaluated: plant height, number of plant-1 leaves, head diameter, lettuce production and lettuce dry mass. Some economic indicators were determined such as: production cost, gross income, net income, rate of return and profitability index of the two crops. There was no interaction between the treatment factors for the production characteristics, with lettuce production of 87.8 kg / 100 m2. There was a statistical difference in the presence and absence of mung beans, with mean values of 81.4 and 67 kg / 100 m2 of lettuce, respectively. The highest economic efficiency in lettuce cultivation occurred in the presence of mung beans in the amount of 3.0 kg m-2, with gross income of 3343.75, net income of 1582.40, rate of return of 1.90 and index of profitability of 43.42%. The use of mung beans in lettuce cultivation is a viable option for the farmer to use.

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