Abstract
A periodic shading mechanism (about 0.5 s period) is believed to be used by flagellated algae to detect light direction. Time changes in the orientation of a population ofHaematococcus pluvialis under positive photoaxis conditions (cell samples were stimulated alternatively by two diametrically opposed beams of actinic light), have been investigated by analysing the Doppler shifts of laser light scattered by the cells by means of heterodyne detection techniques. This technique allows us to measure the mean value of the component of the cells' swimming velocities along the light stimulus axis. Preliminary data indicate that the time taken by a cell population to change orientation is about 1 s.
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References
Ascoli, C., Barbi, M., Frediani, C., Petracchi, D. and Ristori, T. (1980)Optica Acta 27:1203–1212.
Ascoli, C. and Frediani, C. (1980)Light scattering in liquids and macromolecular solutions (Degiorgio, Corti, Giglio, Eds.) Plenum Publishing Corporation.
Colombetti, G. and Petracchi, D. (1989)Photoresponse mechanisms in algal flagellates. CRC Critical Reviews in Plant Sciences, in press.
Foster, K. W. and Smyth, R. D. (1980)Microbiol. Revs. 44:572–630.
Nultsch, W. and Häder, D.-P. (1979)Photochem. Photobiol. 29:423–437.
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Cantatore, G., Ascoli, C., Colombetti, G. et al. Doppler velocimetry measurements of phototactic response in flagellated algae. Biosci Rep 9, 475–480 (1989). https://doi.org/10.1007/BF01117050
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DOI: https://doi.org/10.1007/BF01117050