Osmotic stress in Arctic and Antarctic strains of the green alga Zygnema (Zygnematales, Streptophyta): effects on photosynthesis and ultrastructure.

ABSTRACT: The osmotic potential and effects of plasmolysis on photosynthetic oxygen evolution and chlorophyll fluorescence were studied in two Arctic Zygnema sp. (strain B, strain G) and two Antarctic Zygnema sp. (strain E, strain D). Antarctic strain D was newly characterized by rbcL sequence analysis in the present study. The two Antarctic strains, D and E, are most closely related and may represent different isolates of the same species, in contrast, strain B and G are separate lineages. Incipient plasmolysis in the cells was determined by light microscopy after incubating cells in sorbitol solutions ranging between 200 mM and 1000 mM sorbitol for 3, 6 and 24h. In Zygnema strain B and G incipient plasmolysis occurred at ~600 mM sorbitol solution (720 mOsmol kg(-1), ψ=-1.67 MPa) and in strains D a

SUBMITTER: Kaplan F 

PROVIDER: S-EPMC3523258 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature