ISSN:
1432-1793
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The effects of salinity variation on organic solute accumulation have been studied in marine Enteromorpha intestinalis (L.) Link (St. Andrews, Fife, National Grid Ref. NO 514168, and Fife Ness, Fife, National Grid Ref. NO 638098) collected from upper mid-shore rock pools from January to July 1987; and in freshwater E. intestinalis (Forfar Loch, Angus, National Grid Ref. NO 440504) collected during August 1986, in short-term (48 h) and long-term (35 d) experiments. The tertiary sulphonium compound β-dimethylsulphoniopropionate (DMSP) was the principal organic osmolyte in unstressed cells; marine plants contained greater amounts of DMSP than freshwater plants. Exposure to increased salinity resulted in the short-term accumulation of proline and sucrose, while DMSP was unchanged in freshwater and marine plants. In longer-term exposure to salt stress, sucrose levels declined while DMSP increased and proline levels remained high. Long-term incubation in hypersaline media increased the tissue protein and chlorophyll levels of marine E. intestinalis; this may be linked to changes in the cytoplasm:vacuole ratio of the cell. Prolonged exposure to hyposaline and hypersaline conditions led to changes in DMSP content in the manner predicted for an osmotic effector, suggesting that DMSP is involved in long-term osmoacclimation in Enteromorpha spp. The results are also consistent with the proposal that DMSP acts as a compatible cytosolute in Enteromorpha species.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00391537
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