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Publication
Photosynthetic responses of Lupinus albus to soil water fluctuations
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Advisor(s)
Abstract(s)
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.
Description
Keywords
Drought Photosynthesis Lupinus albus
Citation
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.