Über tagesperiodische Schwankungen der Sauerstoffbilanz kernhaltiger und kernloser Acetabularia mediterranea

Abstract

A method is described for the electrochemical determination of the oxygen balance of aquatic organisms. With this method it was possible to demonstrate that individual Acetabularia cells kept under continuous illumination showed a diurnal rhythm of photosynthesis for a period of several weeks. The rhythm could be observed even 40 days after removal of the nucleus. The role of the nucleus in this periodicity is discussed.

Circadian Systems and Metabolism

“…The rhythm of chloroplast migration continues in cells that have their nucleus removed (Schweiger et al, 1964b;Sweeney and Haxo, 1961). However, when nuclei are transplanted between cells that had been grown in opposite light:dark cycles, the nucleus determines the phase of the chloroplast rhythm (Schweiger et al, 1964a).…”

On the role of gene expression in the circadian oscillator mechanism

“…In A. mediterranea and A. crenulata, the rhythmicity was shown to persist upon enucleation, under appropriate conditions up to 40 days. Although being far from self-evident, this observation is very well documented (Sweeney and Haxo, 1961;Sweeney et al, 1967;Richter, 1963;E. Schweiger et al, 1964a;Vanden Driessche, 1967bVanden Driessche et al, 1970;Schweiger, 1971, 1975;Karakashian and Schweiger, 1976a).…”

Potentiation of Photosynthetic Oxygen Evolution in Red Light by Small Quantities of Monochromatic Blue Light

“…One hour or even 1 minute per day of low intensity blue light, which in itself is insufficient for gro-wth, in addition to red light enables the buhlhri does niot perform as expecte(l. (fig 2, trace 1). This is the well known circadian rhythm of photosynthesis in Acethabil(iriai (13,14,15). In these experiments the phase of the rhythm was always the same, having been set by the 8-hour (9- (19), it is possible that this hehavior is duie to adaptive phenomena and not to aln early (leterioration of the cells.…”