Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T13:30:31Z No. of bitstreams: 5 16.pdf: 2264246 bytes, checksum: 0428b3049c41136d0034fb8c5bcbc678 (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20904 bytes, checksum: e09bf99e64678e4285abf3ef3e05412d (MD5) license_rdf: 23422 bytes, checksum: b145eda3d84bdc4f56b389c0ab98d368 (MD5) license.txt: 2110 bytes, checksum: b4c884761e4c6c296ab2179d378436d4 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T14:56:22Z (GMT) No. of bitstreams: 5 16.pdf: 2264246 bytes, checksum: 0428b3049c41136d0034fb8c5bcbc678 (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20904 bytes, checksum: e09bf99e64678e4285abf3ef3e05412d (MD5) license_rdf: 23422 bytes, checksum: b145eda3d84bdc4f56b389c0ab98d368 (MD5) license.txt: 2110 bytes, checksum: b4c884761e4c6c296ab2179d378436d4 (MD5) / Made available in DSpace on 2015-02-27T14:56:22Z (GMT). No. of bitstreams: 5 16.pdf: 2264246 bytes, checksum: 0428b3049c41136d0034fb8c5bcbc678 (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20904 bytes, checksum: e09bf99e64678e4285abf3ef3e05412d (MD5) license_rdf: 23422 bytes, checksum: b145eda3d84bdc4f56b389c0ab98d368 (MD5) license.txt: 2110 bytes, checksum: b4c884761e4c6c296ab2179d378436d4 (MD5) Previous issue date: 2010 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / A grande demanda de ?leos vegetais no Brasil, gerada pelo Programa Brasileiro de Biodiesel, fez com que o pinh?o manso, uma esp?cie at? ent?o desvalorizada, se tornasse alternativa para fornecimento de mat?ria-prima. Por?m, muitos s?o os estudos que devem ser realizados, antes que se inicie o plantio comercial em larga escala. O manejo correto da aduba??o eleva o lucro do produtor de duas formas. Primeiro, evita o gasto de fertilizantes em quantidades erradas e, depois, favorece o melhor desempenho da planta, proporcionando maior produtividade. Este trabalho objetivou avaliar a resposta do pinh?o manso (Jatropha curcas L.) a doses de NPK no crescimento de plantas e, no crescimento de plantas, produ??o de sementes e de ?leo em duas condi??es edafoclim?ticas. Para tanto, foram montados dois experimentos: o primeiro, em condi??es de casa de vegeta??o, teve os tratamentos dispostos em delineamento inteiramente casualizado, no esquema de fatorial fracionado (4x4x4)1/2, perfazendo 32 tratamentos com tr?s repeti??es, totalizando 96 parcelas experimentais, sendo as doses de N: 0, 75, 150 e 300 mg dm-3, na forma de ur?ia; doses de P: 0, 45, 90 e 180 mg dm-3, na forma de superfosfato triplo e doses de K: 0, 50, 100 e 200 mg dm-3, na forma de cloreto de pot?ssio. Ap?s 120 dias, foram avaliadas as seguintes vari?veis: altura das plantas, di?metro do caule, massa seca da parte a?rea e de ra?zes; an?lise qu?mica do solo ap?s a colheita das plantas e teor de macro e micronutrientes na parte a?rea das plantas. O segundo foi conduzido em campo, em duas condi??es edafoclim?ticas, em Diamantina e Governador Valadares, Minas Gerais. Ambos foram conduzidos da mesma forma: o delineamento utilizado foi o delineamento em blocos casualizados no esquema de fatorial fracionado (4x4x4)1/2, perfazendo 32 tratamentos. Foram aplicadas doses de N: 0, 25, 50 e 100 kg ha-1, na forma de ur?ia; doses de P2O5: 0, 75, 150 e 300 kg ha-1, na forma de superfosfato triplo e as doses de K: 0, 50, 100 e 200 kg ha-1, na forma de cloreto de pot?ssio. Foram avaliados o crescimento das plantas pela medi??o da altura de plantas e di?metro na altura do colo do caule a cada 30 dias; produ??o de sementes e de ?leo com uma colheita em Diamantina, em 2009, e duas colheitas em Governador Valadares, em 2008 e 2009. As plantas responderam negativamente ? adi??o de N e positivamente ao P e K , mostrando que o pinh?o manso ? eficiente na absor??o de N, que foi suprido pela mat?ria org?nica do solo. J? em campo, o pinh?o manso apresentou comportamentos distintos nas duas condi??es edafoclim?ticas. Em Governador Valadares, houve resposta positiva ? aplica??o de N e, em Diamantina, resposta negativa a N e positiva a P. N?o houve resposta a K em campo, indicando que o teor do solo foi suficiente para suprir a planta em todas as fases. No experimento de vaso, as doses de P e K recomendadas foram 25 e 67 mg dm-3, respectivamente. Os n?veis cr?ticos, correspondentes ?s doses recomendadas, foram de 10,6 para P e 74,0 mg dm-3 para K no solo (Mehlich-1). Para os teores na massa seca da parte a?rea do pinh?o manso foram de 3,74; 0,18 e 3,57 dag kg-1 para N, P e K, respectivamente. As doses recomendadas de P para o crescimento, a produ??o de sementes e de ?leo de pinh?o manso em Diamantina foram de 87, 72 e 72 kg de P2O5 por ha, respectivamente. Em Governador Valadares, n?o houve recomenda??o de aduba??o nitrogenada para a fase de crescimento das plantas; para a produ??o de sementes e de ?leo, a dose recomendada foi de 36 e 31 kg ha-1 de N, respectivamente. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2010. / ABSTRACT The great demand for vegetable oils in Brazil, generated by the Brazilian Biodiesel Program, made the physic nut, a devalued specie, become an alternative for providing raw material. However, many studies must be carried out before beginning the large-scale commercial growing. The accurate fertilization increases the producer's profit in two ways, first avoids the fertilizers expense in the wrong quantities and then promotes better plant performance for higher productivity. This study evaluated the physic nut (Jatropha curcas L.) response to NPK doses on seedlings growth and plant growing, seed and oil production in two edaphic and climate conditions. Therefore, there were arranged two experiments: the first, in controlled conditions, was arranged in a completely randomized design, in the fragmented factorial scheme (4x4x4)1/2 comprising 32 treatments with three replicates totaling 96 plots and the N doses: 0, 75, 150 e 300 mg dm-3, in the urea form; P doses: 0, 45, 90 and 180 mg dm-3, in the triple superphosphate form and K doses K: 0, 50, 100 and 200 mg dm-3, in the potassium chloride form. After 120 days, there were evaluated the following variables: seedlings height, stem diameter, the shoot and roots dry mass and nutrients content in the soil and in the seedling shoot macronutrients and micronutrients. The second was conducted in field conditions on two places with distinct edaphic and climate conditions, Diamantina, MG and Governador Valadares, MG. Both were conducted in the same way, the design was in randomized blocks, in the fractional factorial scheme (4x4x4) 1 / 2. The N doses were applied: 0, 75, 150 and 300 mg dm-3, in urea form; P doses: 0, 45, 90 and 180 mg dm-3, in the form of triple superphosphate and K doses: 0, 50, 100 and 200 mg dm-3, in the potassium chloride form. There were evaluated the plants growth by the measure of plants height, stem diameter every 30 days, seeds and oil production with one harvest in Diamantina in 2009 and two harvests in Governador Valadares in 2008 and 2009. Seedlings responded negatively to N addition and positively to P, showing that physic nut is efficient in N uptake that was supplied by soil organic matter. Therefore, in the field physic nut showed different behavior in both edaphic and climate conditions. In Governador Valadares there was positive response to N application and in Diamantina there was negative response to N and positive for P. There was no response to K in either experiment, indicating that the content of the soil was sufficient to supply the plant at all stages. Seedlings responded negatively to N addition and positively to P. There was no response to K field, indicating that the content of the soil was sufficient to overcome the plant at all stages. In pot experiment the recommended doses of P and K were 25 and 67 mg dm-3, respectively. The critical level corresponding to the recommended dose, were 10.6 for P and 74.0 mg dm-3 for K in soil (Mehlich-1). For contents in shoot dry mass of physic nut seeds were 3.74, 0.18 and 3.57 dag kg-1 for N, P and K, respectively. The P recommended doses for growth, seeds and oil of physic nut in Diamantina was 87, 72 and 72 kg P2O5 per ha, respectively. In Governador Valadares, there was no nitrogen indication for the plants growth phase, for oil and seeds production and the recommended dose was 36 and 31 kg ha-1 N, respectively.

Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T13:30:32Z No. of bitstreams: 5 21.pdf: 686664 bytes, checksum: f9e852e5ec686e883014698e954c4160 (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20626 bytes, checksum: 7851d446050a985bd0603b7c4cee472d (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T16:39:11Z (GMT) No. of bitstreams: 5 21.pdf: 686664 bytes, checksum: f9e852e5ec686e883014698e954c4160 (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20626 bytes, checksum: 7851d446050a985bd0603b7c4cee472d (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Made available in DSpace on 2015-02-27T16:39:11Z (GMT). No. of bitstreams: 5 21.pdf: 686664 bytes, checksum: f9e852e5ec686e883014698e954c4160 (MD5) license_url: 49 bytes, checksum: fd26723f8d7edacdb29e3f03465c3b03 (MD5) license_text: 20626 bytes, checksum: 7851d446050a985bd0603b7c4cee472d (MD5) license_rdf: 19710 bytes, checksum: aa65da15f424ff71c620a992a187295c (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) Previous issue date: 2009 / O pinh?o manso tem se apresentado como uma oleaginosa nativa com caracter?sticas importantes para extra??o de ?leo, visando ? produ??o de biodiesel, em ?reas com baixas precipita??es pluviom?tricas e baixos teores de nutrientes no solo. No entanto, pouca import?ncia foi dada ? sua cultura, a qual apenas nos ?ltimos anos vem sendo estudada, o que deixou um grande leque de informa??es em aberto, como as suas limita??es nutricionais e distribui??o dos nutrientes, por exemplo. Os objetivos destes trabalhos foram (a) avaliar as limita??es nutricionais no crescimento de mudas de pinh?o manso em Neossolo Quartzar?nico ?rtico t?pico e (b) avaliar as exig?ncias nutricionais de mudas de pinh?o manso sob omiss?o, ac?mulo e distribui??o de nutrientes nas diferentes partes da planta. Os experimentos foram conduzidos em condi??es de casa de vegeta??o do Departamento de Agronomia da Universidade Federal dos Vales do Jequitinhonha e Mucuri (Diamantina-MG). O primeiro experimento foi realizado com mudas de pinh?o manso cultivadas em vasos contendo Neossolo Quartzar?nico, submetido aos seguintes tratamentos: completo (adubado com N, P, K, Ca, Mg, S, B e Zn), testemunha (solo natural) e a omiss?o de um nutriente por vez (-N, -P, -K,-Ca, -Mg, -S, -B e -Zn), disposto em delineamento inteiramente casualizado, com cinco repeti??es. Ap?s 100 dias, foram avaliadas as seguintes caracter?sticas: altura das mudas, di?metro do caule, peso de massa seca da parte a?rea e das ra?zes e teor de macro e micronutrientes na massa seca da parte a?rea. O segundo foi conduzido em delineamento experimental inteiramente casualizado com quatro repeti??es e nove tratamentos. Os tratamentos consistiram de solu??o nutritiva completa e com omiss?o de N, P, K, Ca, Mg, S, B e Zn, pelo uso da t?cnica do elemento faltante. Ap?s 100 dias, foram avaliadas as seguintes caracter?sticas: peso de massa seca do limbo foliar, do pec?olo, da folha completa (limbo foliar + pec?olo), do caule, da parte a?rea e de ra?zes e teor de nutrientes na massa seca de cada parte das mudas de pinh?o manso. Pelos resultados obtidos, pode-se concluir: (1) todos os nutrientes foram limitantes para o crescimento das mudas de pinh?o manso no Neossolo Quartzar?nico, exceto o N, sendo que a sequ?ncia de limita??o nutricional foi P, Mg, Zn, Ca, K, S, B e N; (2) o pinh?o manso foi altamente exigente em todos os nutrientes na fase de crescimento e (3) o ac?mulo total de macronutrientes e micronutrientes se deu na seguinte forma na ordem decrescente: N>K>Ca>P>Mg>S e Fe>Cu>Mn>B>Zn, respectivamente, com maior ac?mulo na folha completa, ocorrendo uma invers?o de maior ac?mulo entre N e K para macronutrientes e Fe e Cu para micronutrientes no caule das mudas de pinh?o manso. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2009. / ABSTRACT The physic nut has been shown as a native oleaginous with important characteristics for oil extraction to the production of biodiesel in areas with low rainfall and low nutrient content in soil. However, little attention was given to its culture, which only in recent years has been studied, leaving a wide range of information in open, as their nutritional limitations and distribution of nutrients. The objectives of this work were (a) assess the nutritional limitations on physic nut seedling growth in tipic Ortic Quartzarenic Neossol and (b) assess the nutritional requirements of physic nut seedlings under omission, accumulation and distribution of nutrients in different parts of the plant. The experiments were carried out in greenhouse at the Agronomy Departament of UFVJM (Diamantina-MG). The first experiment used the physic nut seedlings, which was cultivated in pots with Quartzarenic Neossol under the following treatments: a complete treatment (fertilized with N, P, K, Ca, Mg, S, B and Zn), a control one (natural soil) and the absence of those nutrients per pot treatment, prepared in a completely randomized design with five repetitions. Plant height, stem diameter, dry weight mass of shoot and roots and content of macro and micronutrients in dry matter shoots were evaluated after 100 days. The second was the experimental design completely randomized, with four replications and nine treatments. The treatments consisted of a complete nutritive solution and with omission of N, P, K, Ca, Mg, S, B and Zn, using the missing element technique. Dry matter of the leaf blade, of the petiole, of the complete leaf (leaf blade + petiole), of the stem, of the shoot and of the roots and the nutrient content in dry matter of each parts of the physic nut seedlings were evaluated after 100 days. By the results, can be concluded: (1) all nutrients were limiting for the physic nut seedlings growth in Quartzarenic Neossol, except for the N, and the nutritional limitation was P, Mg, Zn, Ca, K, S, B and N; (2) the physic nut was highly demanding for all nutrients in the growth phase and (3) the total accumulation of macronutrients and micronutrients in descending order: N>K>Ca>P>Mg>S and Fe>Cu>Mn>B>Zn, respectively, with bigger accumulation in the complete leaf, occurring an inversion of bigger accumulation between N and K for macronutrientes and Fe and Cu for micronutrients in the stem of the physic nut seedlings.

Made available in DSpace on 2014-12-17T15:42:09Z (GMT). No. of bitstreams: 1 DiegoOC_DISSERT.pdf: 2507125 bytes, checksum: a9d27b2c33e87a3e7fac54693ff566a3 (MD5) Previous issue date: 2013-07-18 / The objective of this study was to analyze the oxidative stability of biodiesel from jatropha obtained from different purification processes, three wet processes with different drying (in a vacuum oven, conventional oven and in anhydrous sodium sulfate) and dry (purification with magnesium silicate adsorbent). Raw materials of different qualities (jatropha crop ancient and recent crop) were used. The Jatropha oil was extracted by mechanical extraction and refined. The Jatropha biodiesel was obtained by the transesterification reaction in ethyl route using alkaline catalysis. The biodiesel samples were characterized by analysis of water content, carbon residue, Absorption Spectroscopy in the Infrared Region and Thermogravimetry. Thermogravimetric curves of purified PUsv* PUsq* and had higher initial decomposition temperatures, indicating that the most stable, followed by samples PU* and PUSC*. Besides the sample SP* is a smaller initial temperature, confirming the sample without purification to be less thermally stable. The percentage mass loss of the purified samples showed conversion of about 98.5%. The results of analyzes carbon residue and infrared suggested that contamination by impurities is the main factor for decreased oxidative stability of biodiesel. The oxidative stability was assessed from periodic monitoring, using the techniques of Rancimat, peroxide index, acid value and Pressurized Differential Scanning Calorimetry. Samples of biodiesel from jatropha which showed better oxidative stability were of the best quality raw material and wet scrubbing: PUsq* with dry chemical, using anhydrous sodium sulfate and PUsv* with vacuum drying, which had oxidative stability 6 hours in Rancimat time 0 days, within the limits established by the Technical Regulation No. 4/2012 of the ANP, without the addition of antioxidant, suggesting that these procedures the least influence on the oxidative stability of biodiesel / O objetivo deste trabalho foi analisar a estabilidade oxidativa do biodiesel de pinh?o manso obtido a partir de diferentes processos de purifica??o, sendo tr?s via ?mida com processos de secagens diferentes (em estufa a v?cuo, em estufa convencional e com sulfato de s?dio anidro) e um via seca (purifica??o com adsorvente silicato de magn?sio). Mat?rias primas de diferentes qualidades (pinh?o manso de safra antiga e safra recente) foram utilizadas. O ?leo de pinh?o manso foi extra?do por extra??o mec?nica e refinado. O biodiesel de pinh?o manso foi obtido pela rea??o de transesterifica??o na rota et?lica, utilizando cat?lise alcalina. As amostras de biodiesel foram caracterizadas por an?lises de Teor de ?gua, Res?duo de carbono, Espectroscopia de Absor??o na Regi?o do Infravermelho e Termogravimetria. As curvas termogravim?tricas das amostras purificadas PUsv* e PUsq* apresentaram as maiores temperaturas iniciais de decomposi??o, indicando serem mais est?veis, seguidas das amostras PU* e PUsc*. Al?m da amostra SP* apresentar a menor temperatura inicial, confirmando a amostra sem purifica??o ser a menos est?vel termicamente. Os percentuais de perda de massa das amostras purificadas indicaram convers?o em torno de 98,5%. Os resultados das an?lises de res?duo de carbono e infravermelho sugeriram que a contamina??o por impurezas ? o principal fator para diminui??o da estabilidade oxidativa do biodiesel. A estabilidade oxidativa foi avaliada a partir de monitoramento peri?dico, utilizando as t?cnicas de Rancimat, ?ndice de Per?xido, ?ndice de acidez e Calorimetria Explorat?ria Diferencial Pressurizada. As amostras de biodiesel de pinh?o manso que apresentaram melhor estabilidade oxidativa foram as da mat?ria prima de melhor qualidade e purifica??o por via ?mida: PUsq* com secagem qu?mica, utilizando sulfato de s?dio anidro e PUsv* com secagem a v?cuo, as quais obtiveram estabilidade oxidativa de 6 horas no Rancimat no tempo 0 dias, no limite estabelecido pelo Regulamento T?cnico N? 4/2012 da ANP, sem a adi??o de antioxidante, sugerindo ser estes procedimentos os que menos influenciam na estabilidade oxidativa do biodiesel

Submitted by Natalie Mendes (nataliermendes@gmail.com) on 2015-08-04T01:30:32Z No. of bitstreams: 1 CRIS TESE FINAL.pdf: 3970188 bytes, checksum: 37240b01333f3a3c2c98ce2597450f53 (MD5) / Made available in DSpace on 2015-08-04T01:30:32Z (GMT). No. of bitstreams: 1 CRIS TESE FINAL.pdf: 3970188 bytes, checksum: 37240b01333f3a3c2c98ce2597450f53 (MD5) Previous issue date: 2015-03-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The life cycle of a seed plant involves subsequent stages of development including seed formation, germination and seedling establishment. Together these stages represent the critical phase of intersection between two generations and are characterized by deep cytological, morphological, metabolic and physiological changes. Jatropha curcas L. (Euphorbiaceae) is popularly known as physic nut and produces seeds rich in oil with properties that allow its use in various industries, including the production of biodiesel. This study aimed to advance on the understanding of morphophysiological patterns and elucidate morphoanatomical adaptations involving embryogenesis, maturation, germination and seedling growth in J. curcas. Therefore, it was initially analysed and described the morphophysiological profile based on 13 stages of development and maturation associated to color of the fruit exocarp and seed coat, and description of the structures present at each stage (Chapter 1). Analysis of microtubular cytoskeleton configurations during embryogenesis showed cell cycle activity by the presence of cortical and mitotic microtubules during histodifferentiation and organogenesis, whilst it was possible to characterize a new organogenetic profile of embryogenesis revealed by the presence of a multimeristematic radicle and stomata in embryos of J. curcas seeds (Chapter 2). The multimeristematic embryos formed by a central apical meristem and four lateral meristems interconnected by a complex vascular system have revealed a new model of root formation during seed germination and seedling development, in which there is simultaneous protrusion of a larger main root and four smaller adventitious roots, all growing at the same time during the formation of the seedling root system (Chapter 3). The stomata occurred in the radicle-hypocotyl transition area, exhibited different sizes and ontogenic phases and short lifespan by degenerating during seedling development. This demonstrates it?s functioning as restricted to the simultaneous growth stage of the five roots during germination, apparently due to high demand in gas exchange and energy metabolism, and a likely evolution onto the lenticels present in the stem of this species (Chapter 4). / O ciclo de vida de uma planta com sementes envolve est?dios subsequentes de desenvolvimento, como a forma??o da semente, a germina??o e o estabelecimento da pl?ntula. Essas etapas juntas representam a fase cr?tica de interse??o entre duas gera??es e s?o caracterizadas por profundas mudan?as citol?gicas, morfol?gicas, metab?licas e fisiol?gicas. Jatropha curcas L. (Euphorbiaceae) conhecida popularmente como pinh?o-manso, produz sementes ricas em ?leo com propriedades e aplica??es em diversos setores industriais, incluindo a produ??o de biodiesel. O presente estudo teve como objetivo caracterizar padr?es morfofisiol?gicos e elucidar adapta??es morfoanat?micas envolvendo a embriog?nese, matura??o, germina??o e o crescimento de pl?ntulas de J. curcas. Para tanto, foi inicialmente analisado e descrito o perfil morfofisiol?gico baseado em 13 est?dios de desenvolvimento e matura??o, associados ? colora??o do exocarpo do fruto e do tegumento das sementes e descri??o das estruturas presentes em cada est?dio (Cap?tulo 1). A an?lise das configura??es do citoesqueleto microtubular durante embriog?nese evidenciou atividade do ciclo celular por meio da presen?a de microt?bulos corticais e mit?ticos durante a histodiferencia??o e organog?nese. Foi poss?vel caracterizar um novo padr?o organogen?tico de embriog?nese revelado pela presen?a de rad?cula multimeristem?tica e de est?matos em embri?es de sementes de J. curcas (Cap?tulo 2). Os embri?es multimeristem?ticos, providos de um meristema apical central e quatro meristemas laterais, revelaram um novo modelo de forma??o de sistema radicular durante a germina??o de sementes e desenvolvimento de pl?ntulas, em que h? protrus?o simult?nea de uma raiz principal maior e quatro ra?zes advent?cias menores, todas crescendo ao mesmo tempo, durante a forma??o inicial do sistema radicular da pl?ntula (Cap?tulo 3). Os est?matos ocorrem na ?rea de transi??o hipoc?tilo-rad?cula e exibem diferentes tamanhos e fases ontog?nicas. Estas estruturas apresentaram um curto per?odo de vida, degenerando-se durante o desenvolvimento da pl?ntula, sugerindo seu funcionamento restrito ? etapa de crescimento simult?neo das cinco ra?zes durante a germina??o, aparentemente devido ? alta demanda em trocas gasosas e metabolismo energ?tico, e uma prov?vel evolu??o para as lenticelas presentes no caule desta esp?cie (Cap?tulo 4).