Duração mínima do molhamento foliar no desenvolvimento da ferrugem (Puccinia psidii) e efeito da doença nas respostas fisiológicas do eucalipto

Detalhes bibliográficos
Ano de defesa: 2015
Autor(a) principal: Fonseca, Mariana Duarte Silva
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal do Espírito Santo
BR
Mestrado em Ciências Florestais
Centro de Ciências Agrárias e Engenharias
UFES
Programa de Pós-Graduação em Ciências Florestais
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
630
Link de acesso: http://repositorio.ufes.br/handle/10/5058
Resumo: The rust caused by the fungus Puccinia psidii, is one of the most important diseases of Eucalyptus culture. The objective of this study was to determine the minimum leaf wetness duration (LWD) the infection of P. psidii and development of the disease, as well as the effect of the disease on the physiological responses of Eucalyptus seedlings. The experiment was conducted using a completely randomized design in a 7x2 factorial arrangement – seven time periods of LWD (0, 4, 8, 12, 16, 20, 24 hours) and two clones – using four replicates per treatment; each replication consisted of one inoculated seedling. For inoculation, a suspension containing 2x104 urediniospore mL-1 was prepared and afterwards sprayed on Eucalyptus seedlings by a hand sprayer. After inoculation, the seedlings were enveloped in humid plastic bags for maintain of leaf wetness, then placed under ideal weather conditions of pathogen infection and remained therein according to pre-established LWD time periods. Next, the seedlings were transferred to a climatized greenhouse. We evaluated the latent period, incubation period, incidence, severity, area under the disease progress curve, gas exchange, photosynthetic pigments content and leaf area. The minimum LWD to infection by P. psidii and breakthrough disease was 4 h, although resulting in lower disease severity. Greater severities were observed in treatments as from as from 8 h LWD. The infection of the pathogen and increased severity of the disease negatively affected the physiological responses of seedlings, which caused cutback in net CO2 assimilation rate, stomatal conductance and increased in intercellular CO2 concentration, furthermore, this resulted in the reduction of photosynthetic pigments content and leaf area total of the plant.