Data/hora: 29/05/2024 14:37:48

Biblioteca(s): | Embrapa Mandioca e Fruticultura.
Data corrente: | 25/11/2005
Data da última atualização: | 25/11/2005
Autoria: | RIBEIRO, R. V.; MACHADO, E. C.; OLIVEIRA, R. F. de; PIMENTEL, C.
Afiliação: | ESALQ.
Título: | High temperature effects on the response of photosynthesis to light in sweet orange plant infected with Xylella fastidiosa.
Ano de publicação: | 2003
Fonte/Imprenta: | Brazilian Journal of Plant Physiology, Londrina, v. 15, n. 2, p. 89-97, 2003.
ISSN: | 1677-0420
Idioma: | Inglês
Conteúdo: | The objective of this study was to evaluate the high temperature effects on the response of photosynthesis to light in sweet orange plants infected with Xylella fastidiosa. This vascular bacterium is the causal agent of the citrus variegated chlorosis that causes severe economical losses to the Brazilian citrus industry. The responses of the photosynthetic oxygen evolution and the parameters related to chlorophyll a fluorescence to the increase in light intensity were evaluated at 3°C in both healthy and infected leaf discs. The increase in temperature affected the photosynthetic apparatus of both healthy and infected plants, although infected plants showed higher photochemical sensitivity at the higher temperature (e.g. in the potential quantum efficiency of photosystem II, maximum and basal fluorescence yield, and in the relation between variable and basal fluorescence yield). This higher sensitivity of infected plants was not reflected in the overall photosynthetic reaction, since photosynthetic oxygen evolution values did not vary at 45°C. Healthy and infected plants showed differences in photosynthetic oxygen evolution but displayed similar effective quantum efficiency of photosystem II as well as apparent electron transport rates at 35°C. These results suggest that the limitations in photosynthesis observed on the infected plants might arise through impaired biochemical reactions.
Palavras-Chave: | Chlorophyll fluorescence; light response curve.
Thesagro: | Citrus Sinensis; Xylella Fastidiosa.
Thesaurus Nal: | photosynthesis; temperature.
Categoria do assunto: | --
Registro original: | Embrapa Mandioca e Fruticultura (CNPMF)
Exemplares: | CNPMF - (22327-1) - ADP - AP - -- -  -  -  - DIS