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Sobrado, M. (1999). Drought effects on photosynthesis of the mangrove, Avicennia germinans, under contrasting salinities. Trees, 13(3), 125-130.
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South America: Venezuela
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Drought effects on leaf photosynthesis of A. germinans growing under two contrasting salinities were studied in a Venezuelan fringe mangrove. During both wet and dry seasons, severe chronic-photoinhibition at predawn was not observed but strong down regulation occurred at midday during both seasons. Carbon assimilation rates declined during the dry season in plants from low and high salinity sites, respectively. Significant decrease in leaf photosynthesis was observed. However, a reduction in CO2 diffusion due to lowered stomatal conductance was not large enough to explain the dramatic effect of drought on leaf photosynthesis. Decreased carbon assimilation and photosynthesis leads to reductions in growth. Stomatal response could be mitigated by the capability of A. germinans for osmotic adjustment under high salinity and/or drought. However, this intracellular salt accumulation may reduce carbon assimilation capacity further by decreasing the metabolism of leaf cells, increasing dark respiration and/or photorespiration.
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