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Type: Artigo
Title: Virtual lesions and photosynthetic damage caused by plasmopara viticola in Vitis labrusca
Author: Nogueira Júnior, Antonio F.
Ribeiro, Rafael V.
Marcos, Fernanda C. C.
Amorim, Lilian
Abstract: Downy mildew caused by Plasmopara viticola is the most destructive disease of grapevines. However, the mechanisms of damage caused by P. viticola to photosynthesis in Vitis labrusca remain unknown. Our aim was to quantify the effects of downy mildew on leaf gas exchange in V. labrusca, estimating virtual lesions (regions surrounding lesions where photosynthesis is null) and evaluating limitations imposed on photosynthesis. Grapevine plants cv. Niagara Rosada were inoculated with varying sporangia concentrations of P. viticola to obtain a range of disease severities. Leaf gas exchange and photochemical activity were measured in both diseased and healthy leaves and the eq. Y = (1 - x)β was used to correlate photosynthetic variables (Y) and disease severity (x), with β representing the ratio between virtual and visual lesions. Our results revealed a β-value of 2.79, indicating moderate virtual lesions. Photosynthetic rates decreased by about 83% in leaves with 50% of downy mildew severity and there were significant impairments in the maximum Rubisco carboxylation rate, maximum rate of electron transport driving regeneration of ribulose-1,5-bisphosphate, effective quantum efficiency of photosystem II and mesophyll conductance, even in plants showing less than 10% of downy mildew severity. In conclusion, our results not only reveal how P. viticola affects photosynthesis in V. labrusca, but also give insights into how crop modelling would be improved by taking into account virtual lesions and photosynthetic damage. Such key information is needed for simulation models that quantitatively integrate the interaction between disease and crop growth
Subject: Análise foliar
Country: Países Baixos
Editor: Springer
Rights: Fechado
Identifier DOI: 10.1007/s10658-019-01791-2
Date Issue: Oct-2019
Appears in Collections:IB - Artigos e Outros Documentos
COTUCA - Artigos e Outros Documentos

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