Stochastic noise interferes coherently with a model biological clock and produces specific dynamic behaviour.
The influence of noise is unavoidable in all living systems. Its impact on a model of a biological clock, normally running in regular oscillating modes, is examined. It is shown that in a specific system in which endogenous rhythmicity is produced by a beat oscillator acting on a feedback coupled metabolic pool system, noise can act coherently to produce unexpected dynamic behaviour, running from regular over pseudo-regular to irregular time-structures. If the biological system consists of a set of identical weakly coupled cells, stochasticity may lead to phase decoupling producing irregular spatio-temporal patterns. Synchronization via phase resetting can be achieved by external short-time temperature pulses. Explicit results are obtained for the well-studied circadian photosynthesis oscillations in plants performing crassulacean acid metabolism. Because of the generic structure of the underlying nonlinear dynamics they can, however, be regarded as a general property of the influence of noise on nonlinear excitable systems with fixed points occuring close to limit cycles.
Beck
F
F
Institute of Nuclear Physics, Department of Physics, Darmstadt University of Technology, Schlossgartenstrasse 9, D-64289 Darmstadt, Germany.
Blasius
B
B
Lüttge
U
U
Neff
R
R
Rascher
U
U
D001683:Biological Clocks; D002940:Circadian Rhythm; D019684:Magnoliopsida / Q000378:metabolism; D008954:Models, Biological; D017711:Nonlinear Dynamics; D010788:Photosynthesis; D013269:Stochastic Processes