Analytical Approach to the Study of Circadian Leaf Oscillations in Clover. I. Recording and Spectral Analyses of Leaf Oscillations

Abstract

Problems in the spectral analysis of short oscillatory data records such as are obtained in circadian studies are discussed. The advantages and limitations of Fourier analysis are described and possible errors in parameter estimates are considered. These techniques are applied to a study of the degree of entrainment of the clover leaf (Trifolium repens L.) oscillation by sinusoidally varying white light. The results indicate that entrainment is not an all-or-none response but that frequency components due to both the natural and forcing oscillations may contribute to the leaf movement. A means of automatically recording leaf angle in a form suitable for computer processing is also described.