• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 86
  • 8
  • 4
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 104
  • 104
  • 39
  • 30
  • 28
  • 26
  • 18
  • 16
  • 15
  • 14
  • 13
  • 12
  • 12
  • 8
  • 8
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estimación de la eficiencia del uso del agua (EUA) y Kdpv para plantas jóvenes de Jatropha Curcas L.

Parada Molina, Felipe Agustín January 2014 (has links)
Tesis para optar al grado de Magister en Ciencias Agropecuarias Manejo de Suelos y Aguas Memoria para optar al Título Profesional de Ingeniero Agrónomo / El interés por el cultivo de Jatropha curcas L. ha aumentado en los últimos años. Lo anterior producto de: (1) su potencial bioenergético, y; (2) su eficiencia en el uso del agua, permitiendo su uso en zonas de escasez hídrica. La información disponible sobre este último punto es contradictoria, por esta razón el objetivo de este trabajo fue determinar la eficiencia del uso del agua (EUA) y el coeficiente propuesto por Tanner y Sinclair (1983) (K DPV ) en plantas jóvenes de Jatropha curcas L. El ensayo se realizó en la Región de Coquimbo, Chile (30º13` S, 70º15` O), en plantas de un año. Tres frecuencias de riego fueron establecidas, cada: 8 (T1); 14 (T2), y; 24 días (T3), suministrando agua suficiente para dejar el suelo a capacidad de campo. Se cuantificó la cantidad de agua transpirada por la plantas mediante lisímetros de pesada, en los cuales se consideraron las variaciones de peso como la transpiración del cultivo. Se cuantificó la biomasa producida como materia seca, realizando cortes cada 24 días. Se recopiló la información climática necesaria para determinar el déficit de presión de vapor (DPV) y se realizaron mediciones de potencial hídrico xilemático a mediodía, y de crecimiento (altura, área de sección trasversal de tronco y número de hojas). Los valores obtenidos de EUA y K DPV para Jatropha curcas L. fueron de 4,30 g de materia seca (MS) por cada Mg de agua transpirada y 3,30 g de MS kPa kg -1 de agua transpirada, respectivamente. Jatropha curcas L. presentó valores de - 0,92 y - 0,65 MPa de potencial hídrico xilemático para el periodo más crítico de medición. Respecto a las variables de crecimiento no se encontraron diferencias significativas que respondiesen a los tratamientos aplicados, siendo el T2 el que mostro un mayor crecimiento dentro del presente ensayo en términos de todas las variables medidas. / The interest in Jatropha curcas L. cultivation has increased in the recent years. This is product of its: (1) bioenergy potential, and, (2) efficiency in water use, allowing its use in areas with water scarcity. The literature available on this last point is contradictory, therefore, the objective of this work was to determine the water use efficiency (WUE) and the coefficient proposed by Tanner and Sinclair (1983) (K DPV ) in young plants of Jatropha curcas L. The trial was conducted in the Region of Coquimbo, Chile (30°13'S, 70°15'O), with one year old plants. Three irrigation frequencies were established every: 8 (T1), 14 (T2), and, 24 days (T3), providing enough water to reach field capacity of soil. The amount of transpired water by plants was quantified through weight lysimeters in which the variations were considered as the transpiration of the crop. Produced biomass, in terms of dry matter (DM), was obtained by cutting the plants every 24 days. Weather information was collected to determine the vapor pressure deficit (VPD). The measurements of stem water potential were performed at noon, and growth parameters (as height, cross-sectional area of stem, and number of leaves) were also measured. The obtained values of WUE and K DPV for Jatropha curcas L. were 4.30 g of DM by each Mg of transpired water and 3.30 g of DM kPa kg -1 of transpired water, respectively. Jatropha curcas L. showed values of - 0.92 and - 0.65 MPa of stem water potential for the most critical period of measurement. Regarding growth variables, there was no significant differences observed in the applied treatments, however, the T2 treatment showed a higher growth than other treatments in all the variables measured.
2

Jatropha Curcase in Oahu and Mozambique : Acknowledging scientific differences and resulting questions

Marshall, Lindsey January 2010 (has links)
In the current search for alternatives to fossil energy sources, scientists have expanded their biofuel research pools to include non-traditional crops. Plants that were once only thought of as food crops (for example rapeseed, maize, sugarcane, and sugar beet) are now experimented with and used for biofuel supply. Other plants that did not have any agricultural or commercial use are now integral parts of biofuel research and advancement. One of these plants, Jatropha curcas, has spread through the biofuel communities throughout the world. Jatropha curcas is noted for its high quality oil and ability to grow in poor conditions.  Most of the interest in this tree is concentrated in the tropics, where a year-round growing/harvest season is possible. This study was conducted in order to view and discuss Jatropha curcas in two different settings: two test fields at the Hawaiian Agricultural Research Centers on Oahu, Hawaii, and Sun Biofuels plantation in Chimoio, Mozambique. After visiting Oahu, it was clear that, although some significant steps in pruning techniques had been achieved, many of the questions surrounding jatropha remained unanswered. These questions included, but were not limited to: What is the ideal irrigation level? Is the plant close to domestication? How can optimal yield be achieved? Are there ways to avoid dormancy? Additionally, as a result of the research, many new questions regarding environmental, social, agricultural, and economic aspects of jatropha arose. In Chimoio, it became immediately apparent that the plantation was little more than a huge test plot at its current stage in August, 2009. There was no infrastructure being set-up or built either at Sun Biofuels or in the surrounding cities to accommodate for machine harvesting, crushing, pressing, storage, and transportation, even though the first harvest was scheduled for 2010. Additionally, there were no on-site engineers or scientists to help with the initial phases of growth and harvest. It was evident that jatropha was growing on good quality soil in both Hawaii and Mozambique, and jatropha crops were planted on previous agricultural land. Just because it was shown that jatropha could grow on poor quality land does not mean that it actually grows there in a plantation-like environment. Additionally, because it was been proven that jatropha can grow on good quality soil does not mean it is a competitive substitute for other biofuel crops. It is clear that jatropha has highly irregular qualities (for example, growth, seed content, oil content, oil properties) not just in different parts of the world or even in different plantations, but from genetically identical trees in the same plantation with the same growing conditions. This is an explanation for why jatropha data is so inconsistent across the world. Further scientific and engineering research must be put into jatropha before a company should embark on a large-scale plantation venture. / I dagens sökande efter alternativ till fossila energikällor har forskningen inom biobränsleområdet kommit att inkludera icke-traditionella grödor. Växter som tidigare bara var tänkta som livsmedelsgrödor (t.ex. raps, majs, sockerrör och sockerbetor) ingår idag i experiment och används inom biobränsleutbudet. Andra växter som tidigare inte haft något kommersiellt användningsområde är idag en integrerad del av biobränsleforskningen. En av dessa växter, trädet Jatropha curcas, har spridit sig inom biobränslesamhällen över hela världen. Jatropha är känd för sin högkvalitativa olja och sin förmåga att växa under förhållanden som skulle vara dåliga för andra grödor. Intresset för jatropha är koncentrerat till tropikerna, där skördesäsongen sträcker sig över hela året. Denna studie genomfördes för att undersöka och diskutera Jatropha curcas i två olika miljöer: på The Hawaiian Agricultural Research Center, Oahu, Hawaii samt på Sun Biofuels Plantation, Chimoio, Mozambique. Efter att ha besökt Oahu var det tydligt att även om vissa betydelsefulla framsteg inom beskärningsteknik hade uppnåtts, så är fortfarande många av frågorna kring jatropha obesvarade. Dessa frågor inkluderar, men är inte begränsade till: Vilken är den ideala bevattningsnivån? Kan växten domesticeras? Hur kan optimal avkastning uppnås? Finns det något sätt att undvika trädets naturliga viloperioder? Dessutom, som ett resultat av forskningen, har många nya frågor dykt upp, rörande miljömässiga, sociala, ekonomiska och jordbruksrelaterade effekter av jatrophaodling. I Chimoio blev det uppenbart att Sun Biofuels jatrophaodling, i augusti 2009, inte var mycket mer än en stor försöksanläggning. Ingen infrastruktur vid anläggningen eller i kringliggande städer var inrättad för att möjliggöra maskinell skördning, krossning, pressning, lagring och transportering – trots att första skörden var planerad redan till 2010. Dessutom fanns inga ingenjörer eller forskare på plats för att vara behjälpliga med de inledande faserna av tillväxt och skörd. Relevant data som har samlats in från de två besökta områdena, samt undersökt litteratur, presenteras i resultaten. Det är tydligt att jatropha har mycket varierande egenskaper med avseende på till exempel tillväxt, frönsättning, oljehalt samt oljans egenskaper; inte bara mellan olika delar av världen eller ens mellan olika planteringar, utan också från genetiskt identiska träd i samma plantering med samma odlingsförhållanden. Detta är en förklaring till varför data om jatropha från studier över hela världen är så inkonsekventa. De frågor som uppkom från både Oahu och Chimoio tas upp i diskussionen. Det är uppenbart att ytterligare vetenskaplig och teknisk forskning måste investeras i jatropha innan ett företag kan tänkas ta sig an en storskalig produktion. Det är uppenbart att de två undersökta plantagerna saknar såväl god vetenskaplig kunskap om jatropha som utrustning för dess hantering.
3

Αξιολόγηση της καταλληλότητας ενεργειακών φυτών για καλλιέργεια στην Ελλάδα

Σαραβάκου, Δήμητρα 01 October 2014 (has links)
Τη σημερινή εποχή, η εξάντληση των αποθεμάτων των ορυκτών καυσίμων, σε συνδυασμό με τις αυξανόμενες ενεργειακές ανάγκες, οδήγησε στην παραγωγή των βιοκαυσίμων. Με αυτό τον όρο νοείται κάθε καύσιμο που παράγεται από βιομάζα. Ένα από τα δημοφιλέστερα βιοκαύσιμα στην Ευρώπη είναι το βιοντίζελ, το οποίο λαμβάνεται μετά από μετεστεροποίηση τριγλυκεριδίων που περιέχονται σε φυτικά έλαια και ζωικά λίπη. Οι λόγοι που οδήγησαν στην παραγωγή βιοντίζελ είναι περιβαλλοντικοί αλλά και οικονομικοί, καθώς η αύξηση της χρήσης των ορυκτών καυσίμων επιβάρυνε και συνεχίζει μέχρι σήμερα την ατμοσφαιρική ρύπανση αλλά και η αύξηση της τιμής του πετρελαίου δυσχεραίνει την οικονομική κατάσταση πολλών χωρών που εισάγουν ορυκτά καύσιμα. Στην παρούσα διπλωματική εργασία, παρουσιάζονται τα βιοκαύσιμα 1ης και 2ης γενιάς, οι πρώτες ύλες από τις οποίες προέρχονται, πως αξιοποιούνται, ποια είναι τα πλεονεκτήματα και τα μειονεκτήματα αυτών και στη συνέχεια δίνεται μεγαλύτερη έμφαση στο φυτό Jatropha curcas, το οποίο αποτελεί την πηγή για την παραγωγή βιοντίζελ 2ης γενιάς. Στο τρίτο κεφάλαιο αυτής της διπλωματικής εργασίας, γίνεται παρουσίαση του φυτού, ανάλυση των μορφολογικών χαρακτηριστικών του, περιγραφή της καλλιέργειάς του, των αναγκών του, αναφέρονται οι χώρες στις οποίες έχει διαδοθεί, ο τρόπος επεξεργασίας του, και οι χρήσεις του σε άλλες διεργασίες μέχρι σήμερα. Ακόμη γίνεται γνωστό το κόστος παραγωγής του, η απόδοσή του σε έλαιο και συγκρίνεται με τις βασικές πρώτες ύλες μέχρι στιγμής για την παραγωγή βιοντίζελ. Τέλος, αναφέρονται ευρωπαϊκά και παγκόσμια προγράμματα και πειράματα, στα οποία έχει μελετηθεί η απόδοσή του. / --
4

Isolamento, Purificação e Caracterização de Compostos Ativos de Extratos Antimicrobianos de Jatropha curcas L.

Bastos, Eduardo Muniz Santana 14 January 2014 (has links)
Submitted by Programa de Pós-graduação em Biotecnologia (mebiotec.ufba@gmail.com) on 2017-04-04T12:44:11Z No. of bitstreams: 1 Dissertação Final - Eduardo Muniz.pdf: 8814569 bytes, checksum: d9e8915ece99e537c25c05d3f14bb401 (MD5) / Approved for entry into archive by Delba Rosa (delba@ufba.br) on 2017-07-03T15:51:10Z (GMT) No. of bitstreams: 1 Dissertação Final - Eduardo Muniz.pdf: 8814569 bytes, checksum: d9e8915ece99e537c25c05d3f14bb401 (MD5) / Made available in DSpace on 2017-07-03T15:51:10Z (GMT). No. of bitstreams: 1 Dissertação Final - Eduardo Muniz.pdf: 8814569 bytes, checksum: d9e8915ece99e537c25c05d3f14bb401 (MD5) / CNPq / O pinhão-manso (Jatropha curcas L.) é uma planta oleaginosa, arbustiva, da família das Euforbiáceas, utilizada na medicina popular para o tratamento de diversas enfermidades. Dados da literatura mostram atividades farmacológicas relevantes associadas a diferentes partes da planta, tais como: cicatrizante; hipoglicemiante; hemostático; larvicida, anticancerígeno e antimicrobiano. Por outro lado, a Jatropha curcas L., tem sido apontada como uma importante alternativa para a produção de biodiesel pelo seu alto teor de óleo, sua possibilidade de cultivo em ambientes desfavoráveis e por não competir com a indústria de alimentos. Considerando a possibilidade do incentivo ao seu plantio em consonância com a Política Nacional de Produção e Uso do Biodiesel (PNPB), torna-se evidente que o aproveitamento da biomassa residual gerada na extração do óleo, além de tornar sustentável a cadeia produtiva do biodiesel, pode possibilitar a elaboração de produtos medicinais úteis para a sociedade. Neste trabalho, objetiva avaliar a atividade antibacteriana de extratos de folhas de Jatropha curcas L., e de suas frações, contra bactérias Gram-positivas. O fracionamento do extrato hidroalcoólico bruto foi realizado pela Cromatografia Líquida de Alta Eficiência (CLAE), e testado em ensaio qualitativo, teste do disco, que demonstrou atividade antibacteriana contra o gênero Staphylococcus. Dessa forma, os dados obtidos são importantes, pois direcionam a identificação da substância bioativa antibacteriana presente no extrato de folhas de Jatropha curcas L. que contribuem para o desenvolvimento de novos produtos farmacêuticos além de agregar valor ao vegetal. / The pinhão-manso (Jatropha curcas L.), is an oilseed plant, shrub, the family of Euphorbiaceae, used in folk medicine to treat various diseases. Literature data show relevant pharmacological activities associated with different parts of the plant, such as healing; hypoglycemic; hemostatic; larvicide, anticancer and antimicrobial. Moreover, Jatropha curcas L., has been identified as an important alter-native for biodiesel production for its high oil content, a possibility of growing in harsh environments and not compete with the food industry. Considering the possibility of encouraging its cultivation in line with the National Policy on Production and Use of Biodiesel (NPPB), it becomes clear that the use of residual biomass generated in the extraction of oil, in addition to making a sustainable biodiesel production chain, may enable the development of useful medicinal products for society. This work aimed to evaluate the antibacterial activity of extracts of leaves of Jatropha curcas L., and its fractions against Gram - positive bacteria. Fractionation of the crude hydroalcoholic extract was performed by High Performance Liquid Chromatography (HPLC) and tested in qualitative assay, test disc, which showed antibacterial activity against Staphylococcus. Thus, the obtained data are important because they guide the identification of bioactive antibacterial substance present in the leaf extract of Jatropha curcas L. contributing to the development of new pharmaceutical products as well as adding value to the plant.
5

Aclimatação à salinidade induzida por nitroprussiato de sódio na germinação e no desenvolvimento inicial de plântulas de pinhão-manso / Salt aclimation induced by sodium nutroprusside on germination and early development of Jatropha curcas seedlings

Gadelha, Cibelle Gomes January 2015 (has links)
GADELHA, Cibelle Gomes. Aclimatação à salinidade induzida por nitroprussiato de sódio na germinação e no desenvolvimento inicial de plântulas de pinhão-manso. 2015. 124 f. Dissertação (Mestrado em Bioquímica)- Universidade Federal do Ceará, 2015 / Submitted by Weslayne Nunes de Sales (weslaynesales@ufc.br) on 2016-09-12T12:12:10Z No. of bitstreams: 1 2015_cggadelha_dis..pdf: 1350168 bytes, checksum: 19868b0d8a2badfe7ba36af86ecb4844 (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2016-09-27T17:17:34Z (GMT) No. of bitstreams: 1 2015_cggadelha_dis..pdf: 1350168 bytes, checksum: 19868b0d8a2badfe7ba36af86ecb4844 (MD5) / Made available in DSpace on 2016-09-27T17:17:34Z (GMT). No. of bitstreams: 1 2015_cggadelha_dis..pdf: 1350168 bytes, checksum: 19868b0d8a2badfe7ba36af86ecb4844 (MD5) Previous issue date: 2015 / The jatropha (Jatropha curcas L.) is an oilseed species, belonging to the family Euphorbiaceae, considered a good alternative to agricultural arid and semi-arid regions, such as the Brazilian Northeast. The soil salinization is a common problem in these regions, reducing the productivity of several crops, by negatively affect the growth and plant development. Therefore, it becomes important to carry out studies on the development of this species in salt stress conditions, as well as the assessment of the effects of nitric oxide (NO) in the induction of acclimation to salinity. This study evaluated the effects of pre-treatment of seeds with sodium nitroprusside (SNP), a compound that spontaneously releases NO in solution on germination and early development of jatropha seedlings in salt stress conditions. The concentration of NPS was set in a first experiment, in which jatropha seeds were germinated in germitest moistened sheets of paper with distilled water (pretreatment with water) or with NPS solutions of 50, 75, 100 and 200 M for a period of 24 hours (pre-treatment with SNP). Subsequently, the seeds were transferred to moistened sheets germitest with distilled water (control conditions) or 100 mM NaCl (saline treatment). After eight days after the pre-treatment (DAPT), the pretreated seedlings with NPS to 75 uM showed the best performance in saline conditions, mainly due to significant reductions in levels of Na + and lipid peroxidation, and the improvements in mobilization of reserves and growth. Based on this, we performed a second experiment, which aimed to confirm the observed results and expand the studies of pretreatment on physiology, biochemistry and molecular biology of jatropha plants under salt stress. Pretreatment of seeds with NPS to 75 uM resulted in better germination and mobilization of reserves, as well as further growth of seedlings in saline conditions, compared to non-pretreated. Furthermore, the pretreatment was a decrease in the accumulation of Na + and Cl- ions in saline stress conditions. Oxidative damage in the endosperm and embryo axis of jatropha seedlings were attenuated by pretreatment with NPS. This was due, at least in part, to induction of antioxidant system, both enzymatic, nonenzymatic as under conditions of salt stress, as well as the reduction in H2O2 concentration under these conditions. The analysis of gene expression of CAT and GR was consistent with the increase in activity of these enzymes, promoted by pretreatment with NPS under saline conditions. Based on these results, it is concluded that pretreatment with NPS was efficient in inducing acclimatization of jatropha seedlings to salt stress, mainly for allowing a better ionic and redox homeostasis. / O pinhão-manso (Jatropha curcas L.) é uma espécie oleaginosa, pertencente à família Euphorbiaceae, considerada uma boa alternativa agrícola para regiões áridas e semiáridas, como o Nordeste brasileiro. A salinização dos solos é um problema bastante comum nessas regiões, diminuindo a produtividade de diversas culturas agrícolas, por afetar negativamente o crescimento e o desenvolvimento vegetal. Portanto, torna-se relevante a realização de estudos acerca do desenvolvimento dessa espécie em condições de estresse salino, bem como a avaliação dos efeitos do óxido nítrico (NO) na indução da aclimatação à salinidade. Objetivou-se com esse trabalho avaliar os efeitos do pré-tratamento de sementes com nitroprussiato de sódio (NPS), um composto que libera espontaneamente NO em solução, sobre a germinação e o desenvolvimento inicial de plântulas de pinhão-manso em condições de estresse salino. A concentração de NPS foi definida em um primeiro experimento, no qual sementes de pinhão-manso foram germinadas em folhas de papel germitest umedecidas com água destilada (pré-tratamento com água) ou com soluções de NPS a 50, 75, 100 e 200 μM, por um período de 24 h (pré-tratamento com NPS). Posteriormente, as sementes foram transferidas para folhas de papel germitest umedecidas com água destilada (condição controle) ou com NaCl a 100 mM (tratamento salino). Decorridos oito dias após o pré-tratamento (DAPT), as plântulas pré-tratadas com NPS a 75 μM foram as que apresentaram melhor desempenho em condições salinas, principalmente devido às reduções significativas nos teores de Na+ e na peroxidação lipídica, e pelas melhoras na mobilização de reservas e do crescimento. Com base nisso, foi realizado um segundo experimento, visando-se ampliar os estudos desse pré-tratamento na fisiologia e na bioquímica das plântulas de pinhão-manso sob condições de estresse salino. O pré-tratamento das sementes com NPS a 75 μM resultou em uma melhor germinação e mobilização de reservas, bem como em um maior crescimento das plântulas em condições salinas, em comparação às não pré-tratadas. Além disso, o pré-tratamento promoveu uma redução no acúmulo dos íons Na+ e Cl-, em condições de estresse salino. Os danos oxidativos no endosperma e no eixo embrionário das plântulas de pinhão-manso foram atenuados pelo pré-tratamento com NPS. Isso se deveu, pelo menos em parte, à indução do sistema antioxidativo, enzimático ou não enzimático, sob condições de estresse salino, bem como pela redução dos teores de H2O2, sob tais condições. A análise da expressão gênica da catalase e da redutase da glutationa foi concordante com o aumento em atividade dessas enzimas, promovido pelo pré-tratamento com NPS sob condições de salinidade. Baseado nos resultados obtidos, conclui-se que o pré-tratamento com NPS foi eficiente na indução da aclimatação das plântulas de pinhão-manso ao estresse salino, principalmente por propiciar uma melhor homeostase iônica e redox.
6

Alterações fisiológicas induzidas por estresses abióticos em plantas jovens de pinhão-manso. / Physiological changes induced by abiotic stresses in physic nut young plants

Silva, Evandro Nascimento da January 2009 (has links)
SILVA, E. N. Alterações fisiológicas induzidas por estresses abióticos em plantas jovens de pinhão-manso. 2009. 129 f. Tese (Doutorado em Bioquímica) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2009. / Submitted by Francisco Lacerda (lacerda@ufc.br) on 2015-01-19T20:05:45Z No. of bitstreams: 1 2009_tese_ensilva.pdf: 724120 bytes, checksum: d092fa84efeb6334630dedccc71d1f6c (MD5) / Approved for entry into archive by José Jairo Viana de Sousa(jairo@ufc.br) on 2015-01-19T21:07:30Z (GMT) No. of bitstreams: 1 2009_tese_ensilva.pdf: 724120 bytes, checksum: d092fa84efeb6334630dedccc71d1f6c (MD5) / Made available in DSpace on 2015-01-19T21:07:30Z (GMT). No. of bitstreams: 1 2009_tese_ensilva.pdf: 724120 bytes, checksum: d092fa84efeb6334630dedccc71d1f6c (MD5) Previous issue date: 2009 / In this work were studied diverse physiological mechanisms, as the osmotic adjustment, photosynthesis, including gas exchange and chlorophyll fluorescence parameters, as well the oxidative responses in physic nuts submitted to different abiotic stresses as: salinity, drought and high temperature. The first experiment aimed to study the effects of increase of the NaCl concentrations (0, 25, 50, 75 and 100 mM) in the ions accumulate (Na+, Cl- and K+) and some growth variables, as well evaluate the water state and the principals solutes (organic and inorganic) involved on the osmotic adjustment of physic nuts plants under this stressful condition. Physic nuts plants showed sensibility to salt stress, presenting a reduction by 50% in dry matter from by 47 mM of NaCl concentration during 15-d. This sensibility should be due the leaf Na+ and Cl- high accumulation, associated a strong reduction in the K+concentration, induced by high Na+ content. On the other hand, physic nuts plants were able osmotic adjust to salinity due a severe decrease on the osmotic potential and increase of leaf water state, principally in the higher NaCl levels. Of the solutes studied, was observed that salt ions (Na+ and Cl-) contributed with the most of the osmotic adjustment, while that the K+contribution was decreased strongly by NaCl. The glycinebetaine compared to proline was more important to the osmotic adjustment of physic nuts leaves, as in the absence as in presence of different NaCl levels in the nutrient solution. The second experiment evaluated the resistance of photosynthetic apparatus of physic nuts plants submitted to different time of exposure (7-d and 14-d of treatment and 3-d of recovery) to salt stress (100 mM of NaCl).The changes caused on photochemistry activity and leaf gas exchange were evaluate by Na+ and Cl- accumulation and decrease of K+/Na+ ratio in the leaves. After 7-d of treatment was observed a major action of osmotic effects. However, after 14-d of treatment, the ionic effects caused by Na+ and Cl- excessive accumulation and by K+/Na+ ratio strong reduction in the leaves, caused permanent damages on the photosynthesis of physic nuts plants due as the stomatal limitations as non-stomatal ones. The third experiment aimed to study the comparative effects between the salt stress (50 mM of NaCl) and water stress (induced for xv PEG 6000), both with osmotic potential of –0.22 MPa on the photosynthesis, water relations and growth of physic nuts plants. T e water stress effects induced for PEG in the leaf growth, electrolyte leakage and leaf gas exchange were more deleterious than by NaCl ones. In the both stresses was observed decrease in the leaf CO2 assimilation due the stomatal and nonstomatal limitations. However, the chlorophyll fluorescence parameters did not affect. The fourth experiment aimed to evaluate the relative contribution of organic and inorganic solutes on the osmotic adjustment of leaves and roots physic nuts plants in different water restriction levels. Of the solutes studied, the K+ and soluble sugar were the most involved in the osmotic adjustment as in the leaves as in roots. Others solutes as, Na+, Cl-, total amino acids and glycibetaine, also presented a effective role in the reduction of osmotic potential in both organs. On the other hand, the leaf proline content, although has increased significantly, was not sufficient to promote an effective participation of this amino acid in the osmotic adjustment of physic nuts plants. The same experiment aimed to observe the isolated and combined effects of water stress and high temperature on the photosynthesis and evaluate the oxidative defenses system in physic nuts plants. The photosynthetic apparatus was more sensitive to water stress than heat ones, been that the combination of them caused deleterious effects yet large in this complex. Additionally, the oxidative damages also were more marked in the combined stress. In general, the data shown that physic nuts plants, although present ability to adjust osmotically to salinity and drought, have their photosynthetic apparatus very affected in this stressful conditions. Even as, the defense system against oxidative damages appears has not been efficient in plants exposure at the drought and heat isolated and combined stresses.
7

AssimilaÃÃo de nitrato e amÃnio na proteÃÃo oxidativa, atividade fotoquÃmica e assimilaÃÃo de CO2 em plantas de Jatropha curcas expostas ao estresse salino / Assimilation of nitrate and ammonium in oxidative protection, photochemical activity and assimilation of CO2 in plants exposed to salt stress Jatropha curcas

Rafael MagalhÃes de AragÃo 03 August 2012 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A salinidade à um fator conhecido por limitar o crescimento e a produtividade das plantas. Dentre os processos afetados està a absorÃÃo e assimilaÃÃo de Nitrato (NO3-). AlÃm disso, a salinidade induz a produÃÃo de espÃcies reativas de oxigÃnio que levam a danos oxidativos e aumento da pressÃo de elÃtrons na cadeia transportadora de elÃtrons fotossintÃticos. Assim, neste presente estudo foram utilizadas diferentes abordagens para testar a hipÃtese de que o processo de assimilaÃÃo do nitrato pode aliviar a pressÃo de elÃtrons atuando como um dissipador e assim mitigar os efeitos negativos da salinidade e toxicidade do amÃnio em plantas de Jatropha curcas. Plantas submetidas à salinidade (NaCl 100 mM) e supridas com NO3- 10 mM mostraram maior absorÃÃo, atividade de NR e conteÃdo de proteÃnas solÃveis quando comparada com plantas supridas com NO3- 1mM. A alta assimilaÃÃo de nitrato de alta foi associada com um maior crescimento foliar, assimilaÃÃo de CO2 e menor dano de membrana em plantas tratadas com NaCl. AlÃm disso, uma melhor performance das plantas sob salinidade e supridas com NO3- 10 mM foi indicada por maior rendimento quÃntico efetivo do PSII e taxa de transporte de elÃtrons e menor excesso de energia ao nÃvel de PSII e quenching nÃo-fotoquÃmico. Em outra abordagem, os dados mostraram que o NO3- exÃgeno e sua assimilaÃÃo podem mitigar a toxicidade do NH4+, especialmente quando combinado com a salinidade, conforme mostrado pelos distÃrbios no metabolismo oxidativo, atividade fotoquÃmica e assimilaÃÃo de CO2. Estes efeitos foram demonstrados quando diferentes razÃes de NO3-/NH4+ foram aplicadas em plantas intactas e discos foliares incubados com tungstato (um inibidor da NR) e dose Ãnica de NH4+ na presenÃa ou ausÃncia de MSO (um inibidor de GS). A atividade da GS em Jatropha curcas foi fortemente aumentada pelo NH4+ permitindo manter nÃveis nÃo-tÃxicos de amÃnia em tecidos sob moderadas/altas concentraÃÃes de amÃnio externos. Paralelamente, quando a relaÃÃo exÃgena de NO3-/NH4+ diminuiu, as plantas sofreram reduÃÃo no acÃmulo de matÃria seca associada com acumulaÃÃo de espÃcies de oxigÃnio, diminuiÃÃo da eficiÃncia fotoquÃmica, surgimento de uma aparente fotoinibiÃÃo e reduÃÃo na assimilaÃÃo de CO2. Tomados em conjunto, os dados obtidos indicam que a assimilaÃÃo de NO3- à capaz de mitigar os efeitos negativos da salinidade e de NH4+ , visto pelo seu efeito de proteÃÃo contra danos oxidativos e por atuar como um dissipador de elÃtrons das membranas tilacÃides minimizando fotodanos e estimulando a assimilaÃÃo de CO2 em plantas de Jatropha Curcas.
8

Profitability aspects of biofuel manufacturers in the Republic of South Africa, 2006

Janse van Rensburg, Evert 09 February 2010 (has links)
Please read the summary in the front matter of this document. / Dissertation (MBA)--University of Pretoria, 2010. / Business Management / unrestricted
9

Avaliação e seleção de genótipos de Jatropha curcas L. / Evaluation and selection of Jatropha curcas L. genotypes

Freitas, Ricardo Galvão de 06 February 2015 (has links)
Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2015-11-26T13:23:06Z No. of bitstreams: 1 texto completo.pdf: 743291 bytes, checksum: e3425380aff3a6f65b79b1e46c8d6381 (MD5) / Made available in DSpace on 2015-11-26T13:23:06Z (GMT). No. of bitstreams: 1 texto completo.pdf: 743291 bytes, checksum: e3425380aff3a6f65b79b1e46c8d6381 (MD5) Previous issue date: 2015-02-06 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Jatropha curcas L. é uma das oleaginosas mais promissoras para a produção de biodiesel e bioquerosene. Por ser um cultivo perene ainda incipiente, a avaliação da produtividade é importante para o seu melhoramento genético. As estimativas de parâmetros genéticos são importantes para a caracterização da estrutura genética da população, para o entendimento genético dos caracteres e para a predição dos ganhos com seleção. O presente estudo avaliou o potencial de produtividade de 78 acessos (assumidos como famílias de meios irmãos) de J. curcas, com 48 e 60 meses, em dois anos de produção (2012/13 e 2013/14). O ensaio foi instalado em Araponga (latitude 20o 39’ S, longitude 42o 32’ W e altitude 823 m), MG, em quatro experimentos, todos em blocos casualizados com quatro repetições e parcelas de quatro plantas, utilizando o espaçamento 2x2m, e duas testemunhas comuns aos experimentos, totalizando 1376 plantas. Os caracteres avaliados foram produtividade de frutos (PF), de grãos (PG) e de óleo (PO), em kg.ha-1, teor de óleo da semente (TO), em %, peso de 50 frutos (P50F) e 100 sementes (P100S), em g, comprimento (CF) e largura (LF) do fruto, e comprimento (CS) e largura (LS) da semente, em mm. Processou-se a estimação de parâmetros genéticos e a predição dos ganhos genéticos com a seleção de indivíduos e clones. Para as produtividades e teor de óleo, os resultados evidenciaram a existência de variabilidade genética entre as famílias e herdabilidades individuais de moderada a média magnitude, entre 0,19 e 0,51, adequadas para a seleção da principal característica a ser explorada, PO (0,50). Com base nos valores de repetibilidade ( > 0,60) dos caracteres PG e PO, duas medições ou colheitas consecutivas são suficientes, uma vez que as famílias mantiveram seus desempenhos relativos ao longo dos dois anos. A seleção, pelo valor genotípico, das 20 plantas superiores quanto à produtividade de óleo proporcionou ganho médio de 162,7%, superior à seleção de plantas pelos valores genéticos aditivos (157%), indicando maiores possibilidades de sucesso com a implantação de plantios clonais. / Jatropha curcas L. is one of the most promising oilseed for the production of biodiesel and bio-kerosene. For being an incipient perennial crop, evaluating productivity is important for your breeding. Estimates of genetic parameters are important for the characterization of the genetic structure of the population to the genetic understanding of the characters and for the prediction of gains from selection. This study evaluated the 78 accessions productivity potential (assumed to families half-sib) of J. curcas, with 48 and 60 months, two years of production (2012/13 and 2013/14). The experiment was conducted in Araponga (latitude 20o 39 'S, longitude 42o 32' W and altitude 823 m), MG, in four trials, all randomized blocks with four replicates and four plants per plot, using the spacing 2x2m, and two common checks to the experiments, totaling 1376 plants. The characters evaluated were fruit yield (PF), grains (PG) and oil (PO), in kg ha-1, seed oil content (TO), in%, weight of 50 fruits (P50F) and 100 seeds (P100S) in g, length (FL) and width (LF) of the fruit, and length (CS) and width (LS) seed, in mm. Was estimated genetic parameters and prediction of genetic gain with selection of individuals and clones. For the yield and oil content, the results showed the existence of genetic variability between individual families and heritability of moderate to medium magnitude, between 0.19 and 0.51, suitable for selecting the main feature to be explored, PO ( 0.50). Based on the repeatability values (> 0.60) for the PG and PO characteristics , two consecutive measurements or harvests are sufficient, since the families retained their relative performances throughout the two years. The selection by the genotypic value, the top 20 plants on the oil yield provided average gain of 162.7%, higher than the plant selection by additive genetic values (157%), indicating greater chances of success with the implementation of clonal plantations .
10

Avaliações bioquímicas e fisiológicas para previsão de desordens nutricionais de macronutrientes no desenvolvimento inicial do pinhão-manso / Physiological and biochemical assessments for prediction of nutritional macronutrient disorders in the initial development on physic nut

Santos, Elcio Ferreira dos 21 February 2014 (has links)
No Brasil, vários trabalhos com pinhão-manso (Jatropha curcas L.) têm estudado a avaliação do estado nutricional, porém são poucas as investigações objetivando caracterizar a marcha de absorção, bem como as respostas bioquímicas e fisiológicas desta espécie ao manejo nutricional. antecipadamente o estado nutricional das plantas. Desse modo, o objetivou-se com este estudo avaliar a marcha de absorção no desenvolvimento inicial do pinhão-manso (Jatropha curcas L.), bem como as omissões de N, P, K, Ca, Mg e de S no crescimento inicial e no comportamento bioquímico e fisiológico dessa espécie e, por fim, prever os quadros sintomatológicos das deficiências. Para alcançar os objetivos propostos foram realizados dois experimentos simultâneos, conduzidos em casa de vegetação, sendo que as plantas foram cultivadas individualmente em vasos contendo solução nutritiva. No primeiro experimento - referente à marcha de absorção - a plantas foram cultivadas em solução nutritiva completa, sendo que as plantas eram retiradas a cada 14 dias para a determinação do acúmulo de massa seca e macronutrientes. No segundo experimento as plantas foram cultivadas em solução completa (controle) e omissão individual de N, P, K, Ca, Mg e de S. Neste experimento foram realizados testes bioquímicos e fisiológicas para a previsão de desordens nutricionais aos 20, 30, 40 e 120 dias após o inicio dos tratamentos. As primeiras manifestações de deficiência foram observadas para o Ca e N, seguidas das de Mg e K, contudo não foram observados sintomas de carência de P e S. As atividades das enzimas redutase do nitrato, da fosfatase ácida e da peroxidase, bem como a avaliação das concentrações de poliaminas, efetuadas no início do desenvolvimento das plantas, demonstraram ser indicadores para previsão das desordens nutricionais de N, P e K, respectivamente. As omissões individuais dos macronutrientes limitaram o desenvolvimento inicial do pinhão-manso, reduziram os teores de clorofila e a taxa fotossintética de forma distinta. Porém, a omissão de Ca foi a que mais limitou o desenvolvimento dessa espécie para todas as variáveis avaliadas / In Brazil, several studies with physic nut (Jatropha curcas L.) have studied the assessment of nutritional status, but there are few investigations aiming to characterize the uptake and the biochemical and physiological responses to nutritional management of this species, for the purpose of prediction the nutritional status of plants. Thus, the objective with this study was to evaluate the uptake in the initial development of physic nut (Jatropha curcas L.), as well as the omission of N, P, K, Ca, Mg and S, to physiological and biochemical assessments, and finally, predicting symptomatology frames deficiencies. To achieve the proposed objectives two experiments were conducted in a greenhouse. The plants were grown individually in pots containing nutrient solution. In the first experiment - uptake of macronutrients - the plants were grown in complete nutrient solution, whereas plants were taken every 14 days for the determination of dry matter and macronutrients accumulation. In the second experiment, the plants were grown in complete solution (control) and the omission of N, P , K , Ca , Mg and S. In this experiment biochemical and physiological tests were performed for predicting nutritional disorders at 20, 30, 40 and 120 days after initiation of treatment. The first manifestations of deficiency were observed for Ca and N, followed by Mg and K, but don\'t were observed symptoms of P and S deficiency. The activities of nitrate reductase, acid phosphatase and peroxidase, as well as the assessment of concentrations of polyamines, made in the early development of the plant, proved to forecast indicators of nutritional disorders of N, P and K, respectively. The individual macronutrients omissions limited the initial development of physic nut, in addition, reduced chlorophyll content and photosynthetic rate differently. However, the omission of Ca was the most limited growth of this species for all variables

Page generated in 0.4807 seconds