Interação patógeno-hospedeiro no patossistema capim limão-ferrugem das folhas e avaliação de ingredientes ativos naturais no controle da doença
Data
2009-02-06
Autores
Lorenzetti, Emi Rainildes [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Cymbopogon citratus (DC.) Stapf é uma gramínea perene, de grande importância para a indústria farmacêutica e alimentícia, fornecedora de óleo essencial. Um problema limitante para a produção comercial é a ferrugem, causada pelo patógeno Puccinia nakanishikii Dietel. O trabalho objetivou estudar a interação patógeno-hospedeiro e availar princípios ativos naturais no controle da doença. Para os estudos anatômicos foram elaborados cortes, objetivando analisar as estruturas lesionadas e o desenvolvimento do patógeno. Foram avaliadas as trocas gasosas nas diferentes severidades da doença. Realizaram-se testes in vitro, com diferentes agentes de controle sobre a germinação de esporos do patógeno, sendo estes: óleos essenciais de eucalipto, palma-rosa, cravo-da-índia, menta, limão, citronela e mil-folhas; extrato pirolenhoso de eucalipto e mentol cristalizado. A partir destes testes foram escolhidos quatro agentes para os testes em campo, óleo de citronela e de eucalipto, extrato pirolenhoso e mentol. A área foi preparada a partir de mudas, sendo manejadas até os seis meses. Quando todas as plantas apresentavam sintomas, iniciaram-se os tratamentos com aplicações semanais. Foi avaliada ainda a doença após um corte. Os sintomas iniciais manifestam-se como manchas amareladas evoluindo para a formação de pústulas bronzeadas alongadas. Quanto à avaliação anatômica, após a infecção houve o desenvolvimento das estruturas fúngicas, prosseguindo com o rompimento da cutícula, possibilitando a observação das estruturas do patógeno de forma clara sobre as células da epiderme. Nas regiões lignificadas dos feixes vasculares não há desenvolvimento dessas estruturas. Com o aumento da severidade da doença observou-se a redução da assimilação de gás carbônico. A concentração interna de gás carbônico foi maior em severidades mais altas. Tal fato relaciona-se...
Cymbopogon citratus (DC) Stapf is a perennial grass, that has a large importance to the pharmaceutical and food industry, supplier of essential oil. One limiting problem to the commercial production is the rust caused by pathogen Puccinia nakanishikii Dietel. This work aimed to investigate the pathogen-host interactions and contribute to the researches with alternative methods of disease control. For anatomical studies were prepared anatomical sections, with the objective to analyze the structures injured and the development of the pathogen with different corants. On cultivated plants were evaluated gas exchange in different severity levels. In vitro tests were performed with different control agents, to the germination of pathogen spores, which are: essential oil of eucalyptus, palmarosa, clove, peppermint, lemon, citronella and yarrow; pyroligneous extract of eucalyptus and crystallized menthol. From these tests four products were chosen for the tests in a camp experiment, citronella oil, eucalyptus oil, pyroligneous extract and menthol. The area was prepared from seedlings, which were managed by six months age. When all plants had symptoms the treatments begin, with weekly applications. One avaliation happened after the cut of the lemongrass. The initial symptoms manifest as yellow spots progressing to formation of elongated pustules. These symptoms beginning with the development of fungal structures, after occurred the disruption of the cuticle, so the structures of the pathogen may be clearly observed on epidermis parenchyma cells of the leaf abaxial surface, however, in regions of vascular bundles, no development of such structures, these regions that have lignified structures. With the increase of the disease severity was a significant reduction in the assimilation of carbonic gas. The internal concentration of carbon dioxide was major... (Complete abstract click electronic access below)
Cymbopogon citratus (DC) Stapf is a perennial grass, that has a large importance to the pharmaceutical and food industry, supplier of essential oil. One limiting problem to the commercial production is the rust caused by pathogen Puccinia nakanishikii Dietel. This work aimed to investigate the pathogen-host interactions and contribute to the researches with alternative methods of disease control. For anatomical studies were prepared anatomical sections, with the objective to analyze the structures injured and the development of the pathogen with different corants. On cultivated plants were evaluated gas exchange in different severity levels. In vitro tests were performed with different control agents, to the germination of pathogen spores, which are: essential oil of eucalyptus, palmarosa, clove, peppermint, lemon, citronella and yarrow; pyroligneous extract of eucalyptus and crystallized menthol. From these tests four products were chosen for the tests in a camp experiment, citronella oil, eucalyptus oil, pyroligneous extract and menthol. The area was prepared from seedlings, which were managed by six months age. When all plants had symptoms the treatments begin, with weekly applications. One avaliation happened after the cut of the lemongrass. The initial symptoms manifest as yellow spots progressing to formation of elongated pustules. These symptoms beginning with the development of fungal structures, after occurred the disruption of the cuticle, so the structures of the pathogen may be clearly observed on epidermis parenchyma cells of the leaf abaxial surface, however, in regions of vascular bundles, no development of such structures, these regions that have lignified structures. With the increase of the disease severity was a significant reduction in the assimilation of carbonic gas. The internal concentration of carbon dioxide was major... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Fitopatologia, Fotossintese, Plantas medicinais, Ferrugem, Capim-limão - Doenças - Controle, Alternative control, Photosynthesis, Essential oils, Puccinia, Cymbopogon, Rust disease, Medicinal plants
Como citar
LORENZETTI, Emi Rainildes. Interação patógeno-hospedeiro no patossistema capim limão-ferrugem das folhas e avaliação de ingredientes ativos naturais no controle da doença. 2009. ix, 78 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas de Botucatu, 2009.