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Previous issue date: 2015-08-20 / CAPES / The glyphosate, herbicide used in different countries, inhibits the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), blocking the synthesis of aromatic amino acids. With this, it still affects the activity of phenylalanine ammonia lyase (PAL) and the concentration of metabolites in plants. Its activity was first reported as a metal chelator. Therefore, to make use of this herbicide, may be formation of complexes with metals from soil, occurring change in the effectiveness of the product and loss of minerals. Thus, to avoid such problems,this study aimed to compare the effectiveness of three forms of glyphosate: purified, previously complexed with metals, and a commercial form (Roundup WG?). The effects of glyphosate complexes with copper, cobalt and nickel with different stoichiometries and different pH values on the in vitro activity of EPSPs were evaluated. Selected complex for the first experiment in vivo were Cu421 and Co821 (first number for pH and the latter two to stoichiometry glyphosate: metal). These complexes were used in the in vivo experiment I, as well as distilled water (control), purified Roundup and glyphosate on transgenic soybean and B. decumbens. In the following experiments (II and III), mineral oil was used in all treatments to reduce leaching of the compounds. The complex selected for continuation of this study was Cu421 due to its emphasis on the results obtained in the first experiment in vivo. When comparing the effect of the compounds in Falker Chlorophyll Index (ICF) of B. decumbens compared to control, there was fall of this index when using Roundup, Cu421 and purified glyphosate (the latter only in the second experiment). Later it was analyzed fresh mass accumulation and collected fresh material for determination of enzyme activities and N-NO3- levels. The complex Cu421 caused a more significant fresh mass reduction and still allowed the increase in the content of soluble nitrate in Brachiaria decumbens, probably due to the presence of nitrate in this complex. In the case of transgenic soybean there was no significant change in ICF. The use of Roundup and the complex did not change significantly the fresh mass accumul ation in this species. The application of the purified glyphosate, however, caused increase in mass accumulation and all treatments altered soybeans in nitrate content. In experiments with mineral oil in B. decumbens, the Cu421 complex inhibited significantly the EPSPs activity, as well as purified Roundup and glyphosate (the latter only in the experiment III). No inhibition occurred in transgenic soybean. All treatments in vivo stimulated PAL activity only on weed, which suggests that the increase in this activity is a consequence of the inhibition of EPSPs and other deleterious effects of compounds on susceptible plants. This study showed that especially Cu421 complex might be used effectively as a herbicide since it inhibits EPSPs, activates the PA,L reduces fresh mass accumulation and influences photosynthesis in the tested weed. Besides, the transgenic soybean showed little sensitive to this compound, which further increases the prospect of using the same as herbicide. / O glifosato, herbicida usado mundialmente, atua inibindo a enzima 5-enolpiruvil-chiquimato- 3-fosfato-sintase (EPSPs), bloqueando a s?ntese de amino?cidos arom?ticos. Com isso, ainda influencia a atividade de fenilalanina am?nia liase (PAL) e a concentra??o de metab?litos nas plantas. A sua primeira a??o reportada foi como agente quelante de metais. Portanto, ao fazer uso deste herbicida, pode haver forma??o de complexos com metais do solo, ocorrendo altera??o da efic?cia do produto e defici?ncia mineral. Assim, de modo a evitar tais problemas, este trabalho teve como objetivo, comparar a efici?ncia de tr?s formas de glifosato: purificado, previamente complexado com metais, e uma das suas formas comerciais (Roundup WG?). Os efeitos de complexos de glifosato com cobre, cobalto e n?quel, sintetizados sob diferentes estequiometrias e valores de pH, foram avaliados sobre a atividade in vitro de EPSPs. Os complexos selecionados para o primeiro experimento in vivo foram: Cu421 e Co821 (primeiro n?mero referente ao pH e os dois ?ltimos ? estequiometria glifosato:metal). Estes complexos foram usados no experimento in vivo I, assim como ?gua destilada (controle), Roundup e glifosato purificado, sobre soja transg?nica e Brachiaria decumbens. Nos experimentos seguintes utilizou-se ?leo mineral em todos os tratamentos para reduzir a lixivia??o dos compostos. O complexo selecionado para continua??o deste estudo foi o Cu421 devido a seu destaque nos resultados obtidos no primeiro experimento in vivo. Ao comparar o efeito dos compostos no ?ndice de Clorofila Falker (ICF) de B. decumbens em rela??o ao controle, observou-se queda deste ?ndice ao usar Roundup, Cu421 e glifosato purificado (este ?ltimo, somente no segundo experimento). Posteriormente foi analisado ac?mulo de massa fresca e coletado material fresco para determina??o das atividades enzim?ticas e dos teores N-NO3-. O complexo Cu421 foi o que provocou maior redu??o da massa fresca e ainda possibilitou o aumento no teor sol?vel de nitrato em B. decumbens, provavelmente devido ? presen?a de nitrato neste complexo. No caso da soja transg?nica n?o houve altera??o significativa de ICF. O uso de Roundup e dos complexos n?o alterou de forma significativa o ac?mulo de massa fresca nesta esp?cie. A aplica??o do glifosato purificado, entretanto, causou incremento no ac?mulo de massa e todos os tratamentos alteraram o teor de nitrato em soja. Nos experimentos com ?leo mineral em B. decumbens, o complexo Cu421 inibiu de forma significativa a atividade de EPSPs, assim como Roundup e glifosato purificado (este ?ltimo, somente no experimento III). Em soja transg?nica n?o houve inibi??o. Todos os tratamentos in vivo estimularam a atividade de PAL somente na gram?nea, permitindo sugerir que o aumento nesta atividade seja consequ?ncia da inibi??o de EPSPs e de outros efeitos delet?rios dos compostos sobre plantas suscept?veis. O presente estudo mostrou que principalmente o complexo Cu421 pode vir a ser utilizado de forma eficaz como herbicida, uma vez que inibe a EPSPs, ativa a PAL, reduz ac?mulo de massa fresca e influencia a fotoss?ntese na planta daninha testada. E, em contrapartida, a soja transg?nica mostrou-se pouco sens?vel a este composto, o que aumenta ainda mais a perspectiva do uso do mesmo como herbicida.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:jspui/1732 |
| Date | 20 August 2015 |
| Creators | SILVA, Soraia John da |
| Contributors | Salles, Cristiane Martins Cardoso de, Santos, Andr? Marques dos, Salles, Cristiane Martins Cardoso de, Sperandio, Marcus Vinicius Loss, Santos, Fabiana Soares dos |
| Publisher | Universidade Federal Rural do Rio de Janeiro, Programa de P?s-Gradua??o em Qu?mica, UFRRJ, Brasil, Instituto de Ci?ncias Exatas |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFRRJ, instname:Universidade Federal Rural do Rio de Janeiro, instacron:UFRRJ |
| Rights | info:eu-repo/semantics/openAccess |
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