Journal article

Effects of increased salinity on gravitaxis in Euglena gracilis

Publication Details
Author(s): Richter P, Börnig A, Streb C, Ntefidou M, Lebert M, Häder DP
Publisher: Elsevier
Publication year: 2003
Volume: 160
Journal issue: 6
Pages range: 651-656
ISSN: 0176-1617


The unicellular freshwater flagellate Euglena gracilis regulates its position in the water column by means of phototactic and gravitactic behavior. Recent experiments have revealed that the cells switch between negative and positive gravitaxis depending upon environmental stimuli such as solar radiation. In this study, the effect of increased salinity on gravitaxis in Euglena gracilis was investigated. In some experiments it was found that salt concentrations up to 5 g L-1 (in some experiments 10 g L-1) increased the motility, velocity and precision of negative gravitactic orientation. Higher salt concentrations decreased all these parameters. At concentrations of about 15 g L-1, cells which did not become immobile, switched from negative to positive gravitaxis. Positive gravitaxis persisted for several hours or even days when the cells were transferred back to standard culture medium. Most of the cells in cultures exposed to salt concentrations above 20g L-1 lost their motility (partial formation of palmella stages) but recovered when transferred back to standard medium or de-ionised water. Post recovery, the cells showed pronounced positive gravitaxis. Additional investigations on the pigmentation, revealed that the cells showed a complete loss of a carotenoid shoulder in the spectrum, which reappeared when the cells were brought back to standard medium.

How to cite
APA: Richter, P., Börnig, A., Streb, C., Ntefidou, M., Lebert, M., & Häder, D.-P. (2003). Effects of increased salinity on gravitaxis in Euglena gracilis. Journal of Plant Physiology, 160(6), 651-656.

MLA: Richter, Peter, et al. "Effects of increased salinity on gravitaxis in Euglena gracilis." Journal of Plant Physiology 160.6 (2003): 651-656.

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