Title

Effects of Calcium, Strontium, and Magnesium on the Coccolithophorid Cricosphaera (Hymenomonas) carterae. II. Cell Division

Document Type

Article

Publication Date

1-20-1976

Publication Title

Marine Biology

ISSN

0025-3162

Volume

34

Issue/No.

1

First Page

17

Last Page

22

Abstract

The effects of calcium-deficiency, magnesium-deficiency and strontium enrichment on cell division in the alga Cricosphaera (Hymenomonas) carterae have been studied. Cell growth was reduced at 10-3 M Ca and was absent at 5x10-4 M Ca and lower concentrations. The addition of Sr to Ca-deficient media enabled cells to divide, the effect increasing with Sr concentration. When 4.6x10-4 M Sr was added to media containing 10-4 M Ca, the rate of division and the final cell concentration were comparable to the control (10-2 M Ca). Strontium was 20 times more effective than Ca. The rate of growth was also examined at various Mg concentrations. Cell division was absent, or nearly so, in Mg concentrations below 4.2x10-5 M. Cell size increased progressively as the Mg concentration decreased; however, the lowest protein concentration was found in the absence of Mg. In media lacking Mg, cells exhibited changes in ultrastructure including rounding-up and apparent fragmentation of chloroplasts and an increase in vacuole size. Also, the number of mitochondria per cell section increased 2.9 times in the absence of Mg while the total cross-sectional area remained the same, indicating fragmentation.

Comments

©Springer-Verlag 1976

Additional Comments

U.S. Public Health Service Research grant #: DE-O1382-O6

DOI

10.1007/BF00390782

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Peer Reviewed

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