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Uptake of Zinc and Strontium by Brown Algae
Author(s) -
SKIPNES OLAV,
ROALD TONE,
HAUG ARNE
Publication year - 1975
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1975.tb03845.x
Subject(s) - zinc , algae , ascophyllum , strontium , seawater , vacuole , intracellular , biophysics , chemistry , brown algae , polysaccharide , isotopes of zinc , living cell , cell wall , biology , botany , biochemistry , ecology , cytoplasm , microbiology and biotechnology , organic chemistry
The accumulation of radioactively labelled strontium and zinc by living and killed tips of the brown alga Ascophyllum nodosum (L.) Le Jol. was studied and compared with the uptake in some model substances. The accumulation of strontium was reversible, and similar in living and killed plants. Equilibrium was established within a couple of days. Strontium accumulation seemed to be an ionexchange process involving the negatively charged intercellular polysaccharides, probably mainly alginate. Only a small fraction of the zinc uptake in living algae seemed to be due to a similar ion exchange with the intercellular polysaccharides. The characteristic features of the zinc uptake was a constant, slow, irreversible accumulation persisting for very long periods of time. In dead algae the uptake was rapid and reversible, indicating that the algae contained zinc‐binding substances which were not directly accessible to the zinc ions in the surrounding seawater before killing. It is proposed that these substances in the living plant are contained in membrane‐surrounded structures, probably vacuoles. These membranes, effectively regulating the zinc uptake in the living cells, are destroyed by killing, making the zinc binding substances directly accessible. The transfer of zinc from the reversible intercellular sites to the irreversible cellular sites continued undisturbed during low‐tide periods. The intercellular charged polysaccharides thus function as ion buffers, allowing ion uptake into the cell at a constant rate, independent of the tidal movements.