Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T13:30:37Z No. of bitstreams: 5 61.pdf: 450363 bytes, checksum: cd83469eae8b523d2f8e1536e42d83d6 (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T19:40:11Z (GMT) No. of bitstreams: 5 61.pdf: 450363 bytes, checksum: cd83469eae8b523d2f8e1536e42d83d6 (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Made available in DSpace on 2015-02-27T19:40:11Z (GMT). No. of bitstreams: 5 61.pdf: 450363 bytes, checksum: cd83469eae8b523d2f8e1536e42d83d6 (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) Previous issue date: 2013 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / O herbicida glyphosate n?o ? seletivo e de largo espectro de controle de plantas daninhas, seu mecanismo de a??o ocorre com a inibi??o da enzima 5-enolpiruvilchiquimato-3-fosfato sintase (EPSPs), acontecendo o bloqueio da rota do ?cido chiqu?mico, precursor de amino?cidos arom?ticos e de outros metabolitos secund?rios. O objetivo deste trabalho foi avaliar as altera??es nas caracter?sticas fotossint?ticas e do uso eficiente da ?gua por plantas de cafeeiro submetidas ? aplica??o de glyphosate. O experimento foi conduzido em casa de vegeta??o utilizando-se tr?s cultivares de caf? (Coffea arabica): Acai? (MG-6851), Catuca? Amarelo (2 SL) e Top?zio (MG-1190) e tr?s subdoses do glyphosate (0,0; 115,2 e 460,8 g ha-1), em esquema fatorial 3x3, com 4 repeti??es. Os cultivares de caf? se diferiram quanto ? atividade fotossint?tica. Com o aumento das subdoses do herbicida, observou-se maiores consequ?ncias negativas sobre as vari?veis fotossint?ticas. Tais efeitos podem ser atribu?dos aos danos diretos na atividade fotossint?tica ou pelos indiretos, afetando o metabolismo da planta. Com a aplica??o do herbicida, as plantas de cafeeiro apresentaram redu??es de taxa transpirat?ria e condutividade estom?tica, por?m menor efici?ncia do uso da ?gua apenas aos 15 DAA na quarta folha. Os cultivares apresentaram efeitos negativos com a aplica??o das subdoses de glyphosate, quanto a transpira??o e condut?ncia estom?tica. Pode-se concluir que o cultivar Acai? apresentou-se mais tolerante, pois n?o mostrou efeitos prejudiciais na efici?ncia do uso da ?gua. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2011. / ABSTRACT The herbicide glyphosate is nonselective and of wide-spectrum weed control; its mechanism of action is the inhibition of the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPs), blocking shikimic acid route, a precursor of aromatic amino acids and other secondary metabolites. The objective of this study was to evaluate the changes in photosynthetic characteristics and of water use efficiency for coffee plants submitted to glyphosate application. The experiment was conducted in a greenhouse using three varieties of coffee (Coffea Arabica): Acai? (MG-6851), Catuca? Amarelo (2 SL) e Top?zio (MG-1190) and, three subdoses of glyphosate (0,0; 115,2 and 460,8 g ha-1), in a factorial 3x3, with four replicates. The coffee cultivars subjected to reduced rates of glyphosate to differ in terms of photosynthetic activity. With the increase in sub dosage of the herbicide, there have been observed more negative consequences on the photosynthetic variables. These effects can be attributed to the direct damages on photosynthetic activity or to the indirect ones, affecting the metabolism of the plant. With the herbicide application, coffee plants presented reduction of perspiration rate and stomatal conductivity, however less efficiency in water use only at 15 DAA, on the fourth leaf. The cultivars presented negative effects with the application of a sub dosage of glyphosate regarding perspiration and stomatal conductivity. It can be concluded that the cultivar Acai? showed to be more tolerant, as it did not show prejudicial effects in water use efficiency.