Metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados
The synthesis and accumulation of reserve proteins in seeds require a large supply of reduced nitrogen. Generally, the transport of nitrogen from other parts of the plant involves a few specific compounds, the nature of which depends on the species and growth conditions. The fixation of N 2 by Rhizo...
| Autor principal: | GOMES, Maria Auxiliadora Feio |
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| Grau: | Dissertação |
| Idioma: | por |
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Universidade Estadual de Campinas
2018
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http://repositorio.ufpa.br/jspui/handle/2011/9705 |
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ir-2011-9705 |
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ir-2011-97052018-04-10T05:25:43Z Metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados GOMES, Maria Auxiliadora Feio SODEK, Ladaslav http://lattes.cnpq.br/2012001011713124 Soja Ontogenia Biologia do desenvolvimento Botânica CNPQ::CIENCIAS BIOLOGICAS::BOTANICA::MORFOLOGIA VEGETAL The synthesis and accumulation of reserve proteins in seeds require a large supply of reduced nitrogen. Generally, the transport of nitrogen from other parts of the plant involves a few specific compounds, the nature of which depends on the species and growth conditions. The fixation of N 2 by Rhizobium in symbiotic association with soybeans, cultivated in the absence of mineral nitrogen, leads to the incorporation of atmospheric nitrogen in ureides (allantoin and allantoic acid). These compounds form the main nitrogenous components found in the transport stream of nodulated soybeans. On the other hand, soybeans grown in the absence of Rhizobium and with NO3 nitrogen source, contain asparagine as the predominant as transport form of nitrogen. The accumulation of protein in the fruits of such plants will depend, therefore, on their ability to utilize these compounds for the synthesis of amino acids. The objectives of the present study were: first, demonstrate the presence of the enzymes presumed to be involved in the utilization of these compounds (i.e. allantoinase and asparaginase). Second, determine the effect of this drastic change in the transport of nitrogen from mainly ureides (nodulated plants) to asparagine (non-nodulated plants) on the appearance of these enzymes during fruit ontogeny specifically in the pods, cotyledons and teguments Asparaginase was assayed by a radiometric method, involving the separation of the product by chromatograpy. Allantoin was assayed by measuring the formation of the product by a differential method. Activity of both enzymes was found in all tissues of the fruit, except in the pod where no asparaginase activity was detected. Both allantoinase and asparaginase presented low activities in the tegument, producing only a small peak near the and of seed development, both for modulated and non-nodulated plants, In pods and cotyledons higher levels of allantoinase were found, especially during the phase of most active protein accumulation. It is noteworthy that the activity in the cotyledon was well above the rate of nitrogen accumulation. Asparaginase activity was also higher over this period of cotyledon development, although the level of activity was lower, being similar to the rate of nitrogen accumulation. A comparison of the activity patterns nodulated and non-nodulated plants reveals little difference except for a tendency for allantoinase to remain high (pod and cotyledons) over a longer period in nodulated plants. This occurred in spite of a shorter maturation period for fruits of nodulated plants. On the other, asparaginase (cotyledon) maintained high activity over a longer period in the non-nodulated plants. The possible significance of this effect was discussed in terms of the supply of ureides and asparagine to the fruits. As to the levels of ureides and amino acids in the various fruits tissues, the data show that the ureides, despite their association with nodule activity, were present in levels above that expected for non-nodulated plants. Of the fruit only the pods presented a high level of ureides (200 x) in nodulated plants compared to non-nodulated since low but similar levels were found ín the cotyledons and teguments of both plant types. It is notworthy that the level of free amino acids was generally the inverse of that for ureides, since higher levels were found in fruits of non-nodulated plants. CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior A síntese e acúmulo de proteínas na semente necessita de um grande suprimento de nitrogênio reduzido. Normalmente o transporte deste nitrogênio de outras partes da planta envolve alguns compostos específicos, dependendo da espécie e condições de crescimento. A fixação de N2 pela associação simbólica soja Rhizobium cultivada em meio sem fonte de nitrogênio mineral leva à incorporação de N atmosférico em ureídeos (alantoína e ácido alantóico), que formam os principais compostos nitrogenados encontrados nas vias de transporte de plantas de soja noduladas. Por outro lado em soja cultivada na ausência de Rhizobium e com NO 3 como fonte de nitrogênio, a asparagina é a forma de nitrogênio predominante nas vias de transporte destas plantas. O acúmulo de proteínas nos frutos destas plantas dependerá, portanto, do aproveitamento destas formas de nitrogênio para a síntese de aminoácidos. Os objetivos deste trabalho foram: Primeiramente, verificar a presença das enzimas provavelmente envolvidas na utilização destes compostos (isto é, alantoinase e asparaginase). Segundo, investigar o efeito dessa mudança no transporte de nitrogênio principalmente de ureídeos (plantas noduladas) para asparagina (não-noduladas)sobre a atividade dest as enzimas durante a ontogenia do fruto, especificamente nos tecidos da vagem, dos cotilédones e do tegumento. A asparaginase foi dosada pelo método radiométrico, após a separação do produto por cromatografia, enquanto que a alantoinase foi dosada medindo-se a formação do produto após a transformação em glioxilato Encontrou-se atividade de ambas as enzimas em todos os tecidos do fruto a não ser da vagem onde não detectou-se atividade da asparaginase. Tanto a enzima alantoinase como asparaginase mostraram baixa atividade no tegumenento, ocorrendo apenas um pequeno pico mais no fim do desenvolvimento da semente, tanto para plantas moduladas como não noduladas. Na vagem e cotilédones a atividade da alantoinase foi mais alta durante a fase de acúmulo de proteína. A atividade nos cotilédones, por exemplo, foi em acima da taxa de acúmulo de nitrogênio. Para a asparaginase a atividade também foi mais alta nesta fase de desenvolvimento dos cotilédones embora o nível de atividade fosse menor, sendo semelhante a taxa de acúmulo de nitrogênio neste tecido. Comparando as curvas de atividade obtidas para plantas noduladas e não-noduladas, houve pouca diferença, havendo apenas uma tendência da alantoinase permanecer alta (vagem e cotilédone) durante mais tempo na planta nodulada (apesar da maturação ter ocorrido mais cedo). Por outro lado, a asparaginase manteve a atividade alta durante mais tempo nas não-noduladas. Foi discutido o possível significado deste resultado em termos do fluxo de ureídeos e asparagina para os frutos. Quanto aos níveis de ureídeos e aminoácidos nos tecidos do fruto, os dados mostraram que os ureídeos, apesar de estarem associados com a atividade do nódulos, foram presentes em nível não tão baixos como esperados nas plantas não-noduladas. E, destes tecidos apenas os da vagem mostraram níveis de ureídeos bem mais altos (200 X) nas plantas noduladas comparado com as não-noduladas, que tanto nos cotilédones como no tegumento o nível de ureídeos foi baixo e semelhante para os dois casos. Fato interessante ocorreu com o níval de aminoácidos que foi geralmente o inverso dos ureídeos, encontrando-se níveis mais altos destes nos tecidos de plantas não-noduladas. 2018-04-09T12:58:05Z 2018-04-09T12:58:05Z 1982 Dissertação GOMES, Maria Auxiliadora Feio. Metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados. 1982. 138 f. Dissertação (Mestrado) - Universidade Estadual de Campinas, Instituto de Biologia, Campinas, 1982. Programa de Pós-Graduação em Biologia Vegetal. Disponível em: <http://repositorio.ufpa.br/jspui/handle/2011/9705>. Acesso em:. http://repositorio.ufpa.br/jspui/handle/2011/9705 por Acesso Aberto application/pdf Universidade Estadual de Campinas Brasil Instituto de Biologia – IB/UNICAMP UNICAMP Programa de Pós-Graduação em Biologia Vegetal – PPGBV/UNICAMP http://repositorio.unicamp.br/handle/REPOSIP/315228 |
| institution |
Repositório Institucional - Universidade Federal do Pará |
| collection |
RI-UFPA |
| language |
por |
| topic |
Soja Ontogenia Biologia do desenvolvimento Botânica CNPQ::CIENCIAS BIOLOGICAS::BOTANICA::MORFOLOGIA VEGETAL |
| spellingShingle |
Soja Ontogenia Biologia do desenvolvimento Botânica CNPQ::CIENCIAS BIOLOGICAS::BOTANICA::MORFOLOGIA VEGETAL GOMES, Maria Auxiliadora Feio Metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados |
| topic_facet |
Soja Ontogenia Biologia do desenvolvimento Botânica CNPQ::CIENCIAS BIOLOGICAS::BOTANICA::MORFOLOGIA VEGETAL |
| description |
The synthesis and accumulation of reserve proteins in seeds require a large supply of reduced nitrogen. Generally, the transport of nitrogen from other parts of the plant involves a few specific compounds, the nature of which depends on the species and growth conditions. The fixation of N 2 by Rhizobium in symbiotic association with soybeans, cultivated in the absence of mineral nitrogen, leads to the incorporation of atmospheric nitrogen in ureides (allantoin and allantoic acid). These compounds form the main nitrogenous components found in the transport stream of nodulated soybeans. On the other hand, soybeans grown in the absence of Rhizobium and with NO3 nitrogen source, contain asparagine as the predominant as transport form of nitrogen. The accumulation of protein in the fruits of such plants will depend, therefore, on their ability to utilize these compounds for the synthesis of amino acids. The objectives of the present study were: first, demonstrate the presence of the enzymes presumed to be involved in the utilization of these compounds (i.e. allantoinase and asparaginase). Second, determine the effect of this drastic change in the transport of nitrogen from mainly ureides (nodulated plants) to asparagine (non-nodulated plants) on the appearance of these enzymes during fruit ontogeny specifically in the pods, cotyledons and teguments Asparaginase was assayed by a radiometric method, involving the separation of the product by chromatograpy. Allantoin was assayed by measuring the formation of the product by a differential method. Activity of both enzymes was found in all tissues of the fruit, except in the pod where no asparaginase activity was detected. Both allantoinase and asparaginase presented low activities in the tegument, producing only a small peak near the and of seed development, both for modulated and non-nodulated plants, In pods and cotyledons higher levels of allantoinase were found, especially during the phase of most active protein accumulation. It is noteworthy that the activity in the cotyledon was well above the rate of nitrogen accumulation. Asparaginase activity was also higher over this period of cotyledon development, although the level of activity was lower, being similar to the rate of nitrogen accumulation. A comparison of the activity patterns nodulated and non-nodulated plants reveals little difference except for a tendency for allantoinase to remain high (pod and cotyledons) over a longer period in nodulated plants. This occurred in spite of a shorter maturation period for fruits of nodulated plants. On the other, asparaginase (cotyledon) maintained high activity over a longer period in the non-nodulated plants. The possible significance of this effect was discussed in terms of the supply of ureides and asparagine to the fruits. As to the levels of ureides and amino acids in the various fruits tissues, the data show that the ureides, despite their association with nodule activity, were present in levels above that expected for non-nodulated plants. Of the fruit only the pods presented a high level of ureides (200 x) in nodulated plants compared to non-nodulated since low but similar levels were found ín the cotyledons and teguments of both plant types. It is notworthy that the level of free amino acids was generally the inverse of that for ureides, since higher levels were found in fruits of non-nodulated plants. |
| author_additional |
SODEK, Ladaslav |
| author_additionalStr |
SODEK, Ladaslav |
| format |
Dissertação |
| author |
GOMES, Maria Auxiliadora Feio |
| title |
Metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados |
| title_short |
Metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados |
| title_full |
Metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados |
| title_fullStr |
Metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados |
| title_full_unstemmed |
Metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados |
| title_sort |
metabolismo de ureídeos e asparagina durante a ontogenia do fruto de plantas de soja nodulados e não-nodulados |
| publisher |
Universidade Estadual de Campinas |
| publishDate |
2018 |
| url |
http://repositorio.ufpa.br/jspui/handle/2011/9705 |
| _version_ |
1787147451477524480 |
| score |
11.653393 |