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Details van artikel 7 van 11 gevonden artikelen
| Titel: |
Oxalis leaf movements driven by two separate systems |
| Auteur: |
Kumke, Jens M. |
| Verschenen in: |
Biological rhythm research |
| Paginering: | Jaargang 12 (1981) nr. 1 pagina's 87-96 |
| Jaar: |
1981-03 |
| Inhoud: |
The movements of Oxalis acetosella and O. regnellii are narrowed by physiological limits revealing a shape of nearly a square wave. Profound seasonal alterations of the steepness of the two slopes point to the absence of a single limit-cycle oscillation driving leaf movement. It can be demonstrated that the steepness of both slopes depends specifically upon the light-dark ratio of the Zeitgeber without an interdependence. It can be shown that the phase-angle differences of each slope will shift with linear correlation to the duration of the responsible movement. By a mathematical extrapolation a phase-locked point can be calculated for each movement exhibiting that the driving oscillation itself is fixed in phase to the Zeitgeber causing phase shifts of its visible part (leaf movement) by alterations of its amplitude. Thus two separate not self-excited circadian systems (leaf spreading and leaf folding) are postulated performing their driving amplitudes by resonance upon the Zeitgeber. As predicted the moving amplitudes can be reduced increasingly by lowering the light-intensity steps and reducing the exciting influence of the Zeitgeber by this method. Under these conditions leaf spreading and folding behave differently. Further investigations show that under the influence of constant light conditions the oscillation will fade out developing evident changes in the moving shape of the leaf. This development depends upon light intensity and duration of the constant conditions possibly caused by interference of the two control systems or by changes in the internal signal amplification of each control system separately that decides between a self-excitation or a fading out of the oscillation. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 7 van 11 gevonden artikelen
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