Daily and infradian rhythms of circumnutation intensity in Helianthus annuus

Circumnutation in Helianthus annuus L. was investigated by measurements lasting 4-7 weeks using a picture analysis system. The rhythmicity of circumnutation vigour (intensity) with regard to the trajectory length and period of individual circumnutations were examined. Three photoperiod conditions were applied (light/dark (LD), continuous light (LL) and LD followed by LL]. Data were processed by the Fourier analysis. Statistical analysis included the examination of circumnutation mean frequencies and correlation tests. Both parameters, trajectory length and period, revealed a daily (24 h) modulation in LD with a weak correlation between them, whereas in LL no daily modulation of the parameters was observed. After LD-LL transition, the parameters were gradually losing their daily modulation. Despite a very strong modulation of the trajectory length in LD, the period was quite stable in all groups tested, but only in LD were there no statistical differences in the number of circumnutations per 24 h among the plants studied. LD was concluded to be the strong synchronizer, making the plants circumnutate regularly. Regardless of the presence or absence of daily modulation, the infradian (several and more days long) harmonics of the trajectory length were the same in each group. These findings strongly support the view that circumnutation in sunflower, widely known as an ultradian rhythm, also possesses daily and infradian modulations of its intensity. To the authors' knowledge, this is the first report of circumnutation that was obtained by a picture analysis system in such a large time-scale.

[1]  A. Millar,et al.  The Circadian Clock That Controls Gene Expression in Arabidopsis Is Tissue Specific1 , 2002, Plant Physiology.

[2]  A. Johnsson,et al.  A Theory for Circumnutations in Helianthus annuus , 1967 .

[3]  A. Millar,et al.  Circadian dysfunction causes aberrant hypocotyl elongation patterns in Arabidopsis. , 1999, The Plant journal : for cell and molecular biology.

[4]  D. Chapman,et al.  Circumnutation observed without a significant gravitational force in spaceflight. , 1984, Science.

[5]  Involvement of calcium ions in circumnutation of twining shoots , 1995 .

[6]  Unidirectional waves on rings: Models for chiral preference of circumnutating plants , 1994 .

[7]  Anders Johnsson,et al.  Circumnutations: results from recent experiments on Earth and in space , 1997, Planta.

[8]  T. Hashimoto Molecular genetic analysis of left-right handedness in plants. , 2002, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[9]  R. Morillon,et al.  Water permeability and revolving movement in Phaseolus vulgaris L. twining shoots. , 2000, Plant & cell physiology.

[10]  P. M. Badot,et al.  Circumnutation in Phaseolus vulgaris. II. Potassium content in the free-moving part of the shoot. , 1990 .

[11]  D. E. Somers,et al.  The physiology and molecular bases of the plant circadian clock. , 1999, Plant physiology.

[12]  H. Greppin,et al.  Arabidopsis thaliana floral stem elongation: Evidence for an endogenous circadian rhythm , 1998 .

[13]  Harry Smith,et al.  Phytochromes and light signal perception by plants—an emerging synthesis , 2000, Nature.

[14]  Germaine Cornelissen,et al.  Rhythmic nature of thigmomorphogenesis and thermal stress of Phaseolus vulgaris L. shoots , 1997 .

[15]  C. R. McClung Circadian rhythms in plants: a millennial view , 2000 .

[16]  A. H. Brown,et al.  Circumnutations: From Darwin to Space Flights , 1993, Plant physiology.

[17]  C. Kevers,et al.  Involvement of indole-3-acetic acid in the circadian growth of the first internode of Arabidopsis , 1999, Planta.

[18]  D J Cosgrove,et al.  Expansive growth of plant cell walls. , 2000, Plant physiology and biochemistry : PPB.

[19]  J. Casal,et al.  Phytochromes, Cryptochromes, Phototropin: Photoreceptor Interactions in Plants , 2000, Photochemistry and photobiology.

[20]  T. Roenneberg,et al.  Two circadian oscillators in one cell , 1993, Nature.

[21]  A. Millar,et al.  How plants tell the time. , 2000, Current opinion in plant biology.

[22]  A. Sievers,et al.  Proton Efflux from the Outer Layer of the Peduncle of Tulip in Gravitropism and Circumnutation , 1995 .

[23]  P. Badot,et al.  Cell Elongation and Revolving Movement in Phaseolus vulgaris L. Twining Shoots , 1998 .

[24]  W. Engelmann,et al.  Circumnutations of Arabidopsis thaliana Seedlings , 1997 .