Dans le sud du Cameroun, les palmeraies « villageoises » contribuent au développement rural et à la satisfaction des besoins nationaux en corps gras pour l'alimentation humaine et la savonnerie. Entre 1978 à 1991, 13 000 ha de palmeraies villageoises sélectionnées sont implantés avec l'appui technique et financier d'un projet. Puis le verger villageois sélectionné a triplé pour couvrir actuellement environ 40 000 ha. Ces plantations villageoises réalisées sans encadrement ni soutien financier présentent une grande variabilité de pratiques. Ceci soulève deux questions : celle de la valeur agronomique du verger villageois et celle de l'adaptation du conseil technique normatif. Ce travail repose sur une double approche agronomique. La première se fonde sur un diagnostic agronomique régional qui identifie les facteurs limitant les rendements et les pratiques dont ils découlent, afin de retracer des trajectoires de parcelles. La seconde approche est fondée sur une analyse compréhensive de la constitution de la sole, en retraçant l'historique des conditions d'installation de chacune des parcelles et en resituant les exploitations dans leur bassin d'approvisionnement. Un nouveau facteur limitant spécifique des palmeraies villageoises est révélé : la nutrition azotée en phase adulte. L'analyse spatiale et temporelle de la constitution des soles permet d'expliquer la variabilité des pratiques et d'établir des liens entre les conditions d'implantation, de conduite juvénile et des caractéristiques de parcelles adultes. Le contenu du conseil technique est revisité pour l'adapter aux nouvelles situations de parcelles, d'exploitation et d'environnement filière.

<p>Endocrine&ndash / disrupting compounds (EDCs) are exogenous compounds/chemicals which interfere with, or have adverse effects on the production, distribution and function of natural hormones, thereby affecting normal endocrine activity, health and quality of life of both humans and wildlife. The reproductive system is highly susceptible to EDCs due to it being controlled by an array of hormonal signals. The effects of EDCs on the male reproductive system include infertility, decreased sperm count, function and morphology, abnormal development of secondary sex characteristics, reproductive function and sexual behaviour as well as decreased libido. There are various sources by which EDCs enter the environment which include effluents from several industries (mining, agriculture, smelting, hazardous waste sites, manufacturing industries, etc.), sewage treatment effluents, urban and agricultural runoff and effluents which include natural and pharmaceutical chemicals excreted in the urine of humans and domestic livestock, pesticides, polychlorinated biphenyls, dioxins, plasticizers, surfactants, etc. Humans and animals can also be affected by EDCs by consuming food containing endocrine active substances. The growing concern regarding adverse effects due to EDC exposure of humans and wildlife, as well as the increased incidence of EDC contamination has prompted extensive research into the development and validation of screening tests to detect and monitor known EDCs and new substances with endocrine-disrupting capability. These screening tests involve assessing the effect of known and potential EDCs on reproductive function and development as well as&nbsp / hormone production. To assess the effect of EDCs on the reproductive system different methods are employed which include in vitro, in vivo and ex vivo methods. In vitro methods have been suggested as a suitable screening tool for EDC monitoring due to low costs, reduced animal usage, the use of standard and basic equipment as well as the ability to screen a large number of samples with multiple endpoints. Of the available in vitro methods, the minced testes method has been suggested as the most suitable method for screening EDCs and for this reason has been employed in this study. The aim of this study was thus to employ a minced testes method to screen samples for male reproductive toxicity using cell viability and hormone production (testosterone and estradiol) as endpoints.The first objective of this study was to optimize an in vitro testicular cell culture assay by determining both optimal luteinizing hormone (LH)&nbsp / concentration and incubation time needed for testosterone production. Testicular cell cultures were prepared and cells were treated with varying concentrations of LH (10, 1, 0.1, 0.01 and 0 mu/ml) and incubated for 4 hours and 20 hours. Testosterone production was evaluated for each incubation period. Testosterone production was significantly increased for both incubation periods at all LH concentrations tested as compared to the control. For both incubation periods, there was no significant difference in testosterone production between the different LH concentrations tested. From the data obtained, the 4 hour incubation period as well as the LH concentration of 10 mu/ml were selected as optimal for the testicular cell culture assay. The second objective of this study was to determine the effect of Tulbaghia violacea Harv. on the male reproductive system. T. violacea is a plant species indigenous to southern Africa and is used locally as a herbal remedy/medicine to treat several ailments. Cells were treated with varying concentrations of the T. violacea ethanol extract (with/without LH-treatment) and incubated for 4 hours. Hormone production and cell viability were evaluated. The results obtained from this pilot in vitro study demonstrated that the ethanol extract of T.violacea has androgenic properties by significantly increasing LH-induced testosterone production in mouse testes with no significant change in cell viability. The third objective of this study was to assess the effect of Sutherlandia frutescens(L.) R.Br and Artemisia afra Jacq. Ex Willd. on the male reproductive system. S. frutescens and A. afra are also plant species indigenous to southern Africa and used locally as a herbal remedy/medicine to treat several ailments. Ethanol extracts of each plant was prepared and cells were treated with varying concentrations of each extract (0, 156.25, 312.5, 625, 1250,2500 and 5000 &mu / g/ml) with or without LH-treatment and incubated for 4 hours. Cytotoxicity by LDH measurement and hormone production (testosterone and estradiol) were endpoints that were evaluated. The results obtained showed that the ethanol extracts of both plants are not cytotoxic to testicular cells and that A. afra decreases testosterone production at high concentrations. The fourth and final objective of this study was to assess the acute effect of four heavy metals, namely manganese, copper, cadmium and magnesium on the male reproductive system. These heavy metals are used extensively in manufacturing and mining industries. Cells were treated with varying concentrations of each metal salt (200, 100, 50, 25, 12.5, and 6.25&nbsp / &mu / M) with or without LH-treatment and incubated for 4 hours. Endpoints evaluated included cell viability, testosterone and estradiol production. The results obtained showed that manganese, cadmium and copper are highly toxic to testicular cells in vitro and therefore may potentially cause reproductive toxicity.</p>

<p>Endocrine&ndash / disrupting compounds (EDCs) are exogenous compounds/chemicals which interfere with, or have adverse effects on the production, distribution and function of natural hormones, thereby affecting normal endocrine activity, health and quality of life of both humans and wildlife. The reproductive system is highly susceptible to EDCs due to it being controlled by an array of hormonal signals. The effects of EDCs on the male reproductive system include infertility, decreased sperm count, function and morphology, abnormal development of secondary sex characteristics, reproductive function and sexual behaviour as well as decreased libido. There are various sources by which EDCs enter the environment which include effluents from several industries (mining, agriculture, smelting, hazardous waste sites, manufacturing industries, etc.), sewage treatment effluents, urban and agricultural runoff and effluents which include natural and pharmaceutical chemicals excreted in the urine of humans and domestic livestock, pesticides, polychlorinated biphenyls, dioxins, plasticizers, surfactants, etc. Humans and animals can also be affected by EDCs by consuming food containing endocrine active substances. The growing concern regarding adverse effects due to EDC exposure of humans and wildlife, as well as the increased incidence of EDC contamination has prompted extensive research into the development and validation of screening tests to detect and monitor known EDCs and new substances with endocrine-disrupting capability. These screening tests involve assessing the effect of known and potential EDCs on reproductive function and development as well as&nbsp / hormone production. To assess the effect of EDCs on the reproductive system different methods are employed which include in vitro, in vivo and ex vivo methods. In vitro methods have been suggested as a suitable screening tool for EDC monitoring due to low costs, reduced animal usage, the use of standard and basic equipment as well as the ability to screen a large number of samples with multiple endpoints. Of the available in vitro methods, the minced testes method has been suggested as the most suitable method for screening EDCs and for this reason has been employed in this study. The aim of this study was thus to employ a minced testes method to screen samples for male reproductive toxicity using cell viability and hormone production (testosterone and estradiol) as endpoints.The first objective of this study was to optimize an in vitro testicular cell culture assay by determining both optimal luteinizing hormone (LH)&nbsp / concentration and incubation time needed for testosterone production. Testicular cell cultures were prepared and cells were treated with varying concentrations of LH (10, 1, 0.1, 0.01 and 0 mu/ml) and incubated for 4 hours and 20 hours. Testosterone production was evaluated for each incubation period. Testosterone production was significantly increased for both incubation periods at all LH concentrations tested as compared to the control. For both incubation periods, there was no significant difference in testosterone production between the different LH concentrations tested. From the data obtained, the 4 hour incubation period as well as the LH concentration of 10 mu/ml were selected as optimal for the testicular cell culture assay. The second objective of this study was to determine the effect of Tulbaghia violacea Harv. on the male reproductive system. T. violacea is a plant species indigenous to southern Africa and is used locally as a herbal remedy/medicine to treat several ailments. Cells were treated with varying concentrations of the T. violacea ethanol extract (with/without LH-treatment) and incubated for 4 hours. Hormone production and cell viability were evaluated. The results obtained from this pilot in vitro study demonstrated that the ethanol extract of T.violacea has androgenic properties by significantly increasing LH-induced testosterone production in mouse testes with no significant change in cell viability. The third objective of this study was to assess the effect of Sutherlandia frutescens(L.) R.Br and Artemisia afra Jacq. Ex Willd. on the male reproductive system. S. frutescens and A. afra are also plant species indigenous to southern Africa and used locally as a herbal remedy/medicine to treat several ailments. Ethanol extracts of each plant was prepared and cells were treated with varying concentrations of each extract (0, 156.25, 312.5, 625, 1250,2500 and 5000 &mu / g/ml) with or without LH-treatment and incubated for 4 hours. Cytotoxicity by LDH measurement and hormone production (testosterone and estradiol) were endpoints that were evaluated. The results obtained showed that the ethanol extracts of both plants are not cytotoxic to testicular cells and that A. afra decreases testosterone production at high concentrations. The fourth and final objective of this study was to assess the acute effect of four heavy metals, namely manganese, copper, cadmium and magnesium on the male reproductive system. These heavy metals are used extensively in manufacturing and mining industries. Cells were treated with varying concentrations of each metal salt (200, 100, 50, 25, 12.5, and 6.25&nbsp / &mu / M) with or without LH-treatment and incubated for 4 hours. Endpoints evaluated included cell viability, testosterone and estradiol production. The results obtained showed that manganese, cadmium and copper are highly toxic to testicular cells in vitro and therefore may potentially cause reproductive toxicity.</p>

Made available in DSpace on 2016-08-31T13:24:17Z (GMT). No. of bitstreams: 1 PriscilaMEM_DISSERT.pdf: 1230558 bytes, checksum: 2d6cffd1ce469586311e7cb53c76e776 (MD5) Previous issue date: 2014-09-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The arid and semiarid regions have suffered from the problem of water scarcity, rising steadily through periods of drought. In northeastern Brazil, to meet the water needs is common to drill wells, however, due to geological formation of its aquifers, most of these wells has brackish waters. Agriculture and livestock are important activities in these regions and is responsible for much of the water consumption; an alternative to increase the availability of water for agricultural activities would be to use water from shallow wells for irrigation of halophytes or crops tolerant to salinity. Forage crops are considered tolerant plants, mineral nutrition being a very important factor for the production losses is minimal, and, according to several authors nitrogen, can be a reducer of the effects caused by salt stress, and promote the growth of plant. Aiming to evaluate the interactive effect of salinity levels and nitrogen fertilization on yield and chemical composition of Tanzania grass developed this work in a greenhouse in pots , the treatments consisted of five levels of salinity ( S1 = 0 5 dS m -1 , S2 - 1.5 dS m -1 , S3 - 3.0 dS m -1 , S4 - 4.5 dS m -1 and S5 - 6.0 dS m -1 ) and four nitrogen ( N1 = 0, N2 = 0.8, N3 = N4 = 1.6 and 2.3 g pot-1 ) . Evaluated the production components leaf area (LA), fresh weight and dry weight of leaves ( MFF ) and ( MSF ) , crude protein , and macronutrient content of Cl- and Na+ . There was a significant effect for the interaction of salinity and N levels for all components of the production so that as was the high level of salinity production was reduced, even though the level of salinity S3 N rates possible a lower reduction ratio. Generally observed increase in the concentration of nutrients and PB with increasing salinity of irrigation probably due to the concentration effect of these nutrients in the plant since the dry weight was inversely proportional. It was also found that irrigation with high salt inhibited the beneficial effect of nitrogen on the growth of grass Tanzania / As regiões áridas e semiáridas têm sofrido com o problema da escassez de água, passando constantemente por períodos de seca. No Nordeste brasileiro, para suprir as necessidades hídricas é comum a perfuração de poços artesianos, porém, devido a formação geológica dos seus aquíferos, a maioria desses poços apresenta águas salobras. Uma alternativa para aumentar a disponibilidade de água para as atividades agrícolas seria a utilização de água de poços rasos para irrigação de plantas halófitas ou de culturas tolerantes à salinidade. As plantas forrageiras são consideradas plantas tolerantes, e segundo vários autores, o nitrogênio, pode ser um redutor dos efeitos provocados pelo estresse salino, além de promover o crescimento das plantas. Com o objetivo de avaliar o efeito interativo de níveis de salinidade e adubação nitrogenada na produção e na composição química do capim Tanzânia desenvolveu-se o presente trabalho em casa de vegetação utilizando vasos, os tratamentos foram constituídos da combinação de cinco níveis de salinidade (S1 = 0,5 dS m-1, S2 = 1,5 dS m-1, S3 = 3,0 dS m-1, S4 = 4,5 dS m-1 e S5 = 6,0 dS m-1), e quatro doses de nitrogênio (N1 = 0; N2 = 0,8; N3 = 1,6 e N4 = 2,3 g vaso-1), utilizando delineamento em blocos ao acaso com quatro repetições. Avaliaram-se os componentes de produção área foliar (AF), massa fresca e massa seca de folhas (MFF) e (MSF), teores de proteína bruta, macronutrientes e teores de Cl- e Na+. Observou-se efeito significativo para a interação dos fatores salinidade e doses de N para todos os componentes da produção de forma que à medida que foi elevado o nível de salinidade a produção foi reduzida, porém até o nível de salinidade S3 as doses de N possibilitaram uma menor taxa de redução. De uma forma geral observou-se acréscimos nos teores de nutrientes e PB com o aumento da salinidade da água de irrigação provavelmente devido ao efeito de concentração desses nutrientes dentro da planta uma vez que a massa seca foi inversamente proporcional. Verificou-se também que a irrigação com água de elevada salinidade inibiu o efeito benéfico do nitrogênio sobre o crescimento do capim Tanzânia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A expansão da cultura da palma de óleo nas áreas já desflorestadas da Amazônia legal é reconhecida como uma excelente alternativa para a produção de óleo para fins alimentícios e energéticos. O estado de Roraima apresenta as condições edafoclimáticas adequadas para seu desenvolvimento e introdução na estrutura da agricultura familiar. Objetivou-se com este trabalho desenvolver sistemas de cultivos nas entrelinhas da palma de óleo em área de floresta alterada, durante o período inicial de desenvolvimento da cultura, bem como, avaliar o potencial produtivo de três cultivares de palma de óleo em áreas de savana e floresta alterada de Roraima. Foram avaliados diferentes experimentos e conduzidos em áreas de floresta alterada e savana de Roraima. Para os sistemas de cultivo consorciados com palma de óleo o delineamento foi em blocos casualizados com três repetições, sendo utilizado oito tratamentos compostos por: palma de óleo x banana x feijão caupi; palma de óleo x abacaxi; palma de óleo x mandioca; palma de óleo x feijão caupi x milho; palma de óleo x milho x mandioca; palma de óleo x feijão caupi; palma de óleo x amendoim e palma de óleo em sistema solteiro. Para o desempenho produtivo das três cultivares de palma de óleo o delineamento foi em blocos casualizados com seis repetições e três tratamentos em dois ambientes. No primeiro experimento foi avaliado o desenvolvimento vegetativo da palma de óleo por meio da circunferência do coleto, comprimento da folha 9, largura e espessura do ráquis, número de folíolos da folha 9 e número de folhas emitidas por planta aos 02 e 18 meses após o plantio (local A) e aos 12 e 28 meses após o plantio (local B). Por outro lado, nas avaliações das cultivares BRS C-2528, BRS C-3701 e BRS C-2301 da palma de óleo foram realizadas análises conjuntas dos períodos de 4 a 6 anos de idade, quanto ao número de cachos ha-1, peso médio e produção total de cachos ha-1. Conclui-se que os sistemas que favoreceram o crescimento vegetativo da cultura da palma de óleo foram os sistemas consorciados com feijão caupi x milho, amendoim e mandioca, mostrando-se também economicamente viáveis e podendo ser indicados como alternativa económica para produção de palma de óleo voltada para agricultura familiar. As cultivares de palma de óleo no ambiente de floresta alterada, apresentaram desempenho produtivo superior ao obtido no ambiente de savana. / The expansion of oil palm cultivation in already deforested areas of Amazonia is recognized as an excellent alternative for the production of oil for food and energy purposes. The state of Roraima has the appropriate environmental conditions for its development and introduction in the structure of family farming. The objective of this work is to develop systems of crops between the rows of oil palm in an area of disturbed forest, during the initial period of development of culture, as well as evaluate the productive potential of three intraspecific varieties of oil palm in areas of savanna and forest changed from Roraima. To achieve the objectives were different and conducted experiments in areas of disturbed forest and savannah of Roraima. For intercropping systems with cultivation of palm oil had a randomized block design with three replications, and treatments for the compounds: palm oil x banana x cowpea; palm oil x pineapple; palm oil x cassava; oil palm x cowpea x maize; oil palm x cassava x maize; oil palm x cowpea; oil palm x peanuts and palm oil in single system. For the productive performance of three cultivars of palm oil had a randomized with six replications and three treatments in two blocks environments. In the first experiment evaluated the vegetative development of oil palm through the girth circumference, 9 leaf length, width and thickness of the rachis, number of leaflets leaf 9 and number of leaves per plant issued at 2:18 months after planting ( site A) and at 12 and 28 months after planting (Site B) . Moreover, evaluations of BRS C - 2528, 1 BRS C - 370 and BRS C - 2301 of oil palm joint analyzes of the periods 4-6 years old , as the number of clusters ha-1 were performed, weight average and total production of ha-1 clusters. We conclude that systems favored the vegetative growth of the crop of oil palm were the cowpea intercropping systems with x maize, groundnuts and cassava, proving to be economically viable and may also be indicated as a cheap alternative for the production of palm oil facing family farmers. Cultivars of oil palm in the disturbed forest environment, showed higher than in the savanna environment productive performance.