Affiliation:
1. Instututo di Biofisica del C.N.R., Via S. Lorenzo 26, 56100 Pisa, Italy
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 of Haematococcus 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.
Subject
Cell Biology,Molecular Biology,Biochemistry,Biophysics
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2 articles.
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1. Light Scattering Techniques in Studying Photoresponses;Biophysics of Photoreceptors and Photomovements in Microorganisms;1991
2. Mechanisms and Strategies of Photomovements in Flagellates;Biophysics of Photoreceptors and Photomovements in Microorganisms;1991