caa a22 4500 606220267 CHVBK 20210128101122.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s11104-015-2489-2 doi (NATIONALLICENCE)springer-10.1007/s11104-015-2489-2 The response of the mangrove Avicennia marina to heterogeneous salinity measured using a split-root approach [Elektronische Daten] [Ruth Reef, Hannah Markham, Nadia Santini, Catherine Lovelock] Aims: To investigate the physiological processes underlying freshwater utilisation in halophytes under non-uniform salinity conditions in order to determine whether preferential uptake of freshwater occurs and whether transient freshwater availability improves plant water relations and photosynthesis Methods: In a split-root experiment, we grew Avicennia marina (Forssk.) Vierh. at uniform salinity conditions (35:35ppt) and then lowered (35:5ppt) or increased (35:65ppt) salinity to one compartment. Using δ18O-labelled water we calculated the extent of preferential water uptake of either source. Results: When given a 35:5 treatment, A. marina took-up three times more water from the fresher compartment than predicted by a root-weighted-no-salinity-preference model. No difference between compartments was observed in the 35:65 treatment, suggesting that avoidance of the more saline water did not occur. In the 35:5 treatment, stomatal conductance increased within 1.5h, but photosynthetic rates were not enhanced over the 48-h period of the experiment and rapidly decreased in the 35:65 treatment. Conclusions: Avicennia marina responds to transient freshwater patches by increasing water uptake from areas of the root zone where the salinity is better for growth. However, photosynthetic rates respond to the highest salinity in the root zone; thus, reductions in salinity in part of the root zone may enhance water storage in stem tissues but positive effects on photosynthesis may require longer periods. Springer International Publishing Switzerland, 2015 Non-uniform salinity nationallicence Halophyte nationallicence Water relations nationallicence 18O nationallicence Mangrove nationallicence Split root nationallicence Stem water storage nationallicence Reef Ruth Cambridge Coastal Research Unit, The University of Cambridge, CB2 3EN, Cambridge, UK aut Markham Hannah School of Biological Sciences, The University of Queensland, 4072, St Lucia, QLD, Australia aut Santini Nadia Terrestrial Ecohydrology Research Group, University of Technology, PO Box 123, 2007, Sydney, NSW, Australia aut Lovelock Catherine School of Biological Sciences, The University of Queensland, 4072, St Lucia, QLD, Australia aut Plant and Soil Springer International Publishing 393/1-2(2015-08-01), 297-305 0032-079X 393:1-2<297 2015 393 11104 https://doi.org/10.1007/s11104-015-2489-2 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11104-015-2489-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Reef Ruth Cambridge Coastal Research Unit, The University of Cambridge, CB2 3EN, Cambridge, UK aut NATIONALLICENCE 700 1- Markham Hannah School of Biological Sciences, The University of Queensland, 4072, St Lucia, QLD, Australia aut NATIONALLICENCE 700 1- Santini Nadia Terrestrial Ecohydrology Research Group, University of Technology, PO Box 123, 2007, Sydney, NSW, Australia aut NATIONALLICENCE 700 1- Lovelock Catherine School of Biological Sciences, The University of Queensland, 4072, St Lucia, QLD, Australia aut NATIONALLICENCE 773 0- Plant and Soil Springer International Publishing 393/1-2(2015-08-01), 297-305 0032-079X 393:1-2<297 2015 393 11104