Physiological responses of Caloglossa leprieurii (Ceramiales, Rhodophyta) to salinity stress |
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Authors: | Anika S. Mostaert Ulf Karsten Robert J. King |
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Affiliation: | School of Biological Science, The University of New South Wales. Sydney, New South Wales. 2052, Australia;Max-Planck-Institute for Marine Microbiology, Fahrenheitstr. 1. D-28359 Bremen, Germany |
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Abstract: | Marine, estuarine and freshwater isolates of Caloglossa leprieurii (Montagne) J. Agardh exhibit a high salinity tolerance, reflected by broad cell viability and growth rate. Osmotic adjustment is shown to rely to a large extent on ion-transport systems, with K+ and Cl- accumulated in osmotically- significant quantities and active Na+ extrusion. The ion concentrations contribute a large proportion (67–94%) to internal osmotic pressure. The concentration of the organic osmolyte mannitol in all populations was strongly salinity dependent. Mannitol made a lower contribution to the internal osmotic pressure, when compared to ion concentrations, but nonetheless represented an important proportion of the internal osmolality. The response of the three isolates is discussed in relation to the salinity of their respective environments. |
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Keywords: | Caloglossa leprieurii cell viability growth inorganic ions mannitol osmotic adjustment salt-tolerance |
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