Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.1/1066
Título: Photosynthetic responses of Lupinus albus to soil water fluctuations
Autor: Barrote, Isabel
Osório, Maria Leonor
Osório, Júlio
David, Maria Manuela
Correia, Maria João
Palavras-chave: Drought
Lupinus albus
Data: 2002
Citação: Barrote, Isabel; Osório, Maria Leonor; Osório, Júlio; David, Maria Manuela; Correia, Maria João. Photosynthetic responses of Lupinus albus to soil water fluctuations. Trabalho apresentado em VI Simposium Hispano-Portugués de Relaciones Hidricas en las Plantas. In Actas del VI Simposium Hispano-Portugués de Relaciones Hidricas en las Plantas, Pamplona, 2002.
Resumo: Lupinus albus plants were grown in 3 dm3 pots in a semi-controled greenhouse. Two water regimes were imposed: water deficit (S, 47% of soil capacity), and control (T, 86% of soil capacity). Plants water status was monitored through foliar relative water content (TRA) and pre-dawn (ypd) and midday water potential (ymd). Gas exchanges, chlorophyll a fluorescence and photosynthetic capacity (Amax) were measured. Pigments and soluble protein were quantified and antioxidant system enzymes activity was determined. Plants under water deficit were rehydrated and the same measurements and sampling were done again after 48 h (R1) and 72 h (R2). Albeit water availability has diminished from 86% to 47% of soil capacity, there weren’t any remarkable changes on S plants. R1 plants which haven’t shown any alterations neither in Amax nor in stomatal conductance (gH2O), exhibited a significant decrease on net photosynthesis (A), reaching negative values, along with a raise in non-photochemical quenching (NPQ). Presumably this raise should be related with an increase in the xanthophyll cycle deepoxidation state. The significantly increase in Superoxide dismutase (SOD) specific activity in R1 and R2 plants might be related with the activation of Mehler-peroxidase reaction which provokes lumen DpH raising. This can provide photosynthesis protection through VAZ cycle and may justify the NPQ increase.
Peer review: yes
URI: http://hdl.handle.net/10400.1/1066
ISSN: 84-95844-01-X
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