Über die energetische Steuerung der Phytochrom-kontrollierten Chloroplastenverankerung im cytoplasmatischen Wandbelag

Summary An immediate causal linkage between the weak-light chloroplast movement, the increase of chloroplast anchorage and the formation of plasmic fibrils is postulated. In order to find out further evidence for this assumption the energetics of chloroplast anchorage have been investigated. The following results were obtained. 1. The degree of chloroplast anchorage during darkness as well as the light induced increase of chloroplast anchorage depends on ATP produced by oxidative phosphorylation. The inhibition with DNP is reversible with added ATP. 2. In cells with a reduced intracellular ATP-level the chloroplast anchorage is dramatically reduced; the cells have lost their ability to perform a light induced increase of chloroplast anchorage. The cells regain their ability by an addition of ATP but not by ITP. 3. An increase of chloroplast anchorage, brought about by a cold period of few minutes cannot be reversed by far-red but by high-intensity short-waved light. It is assumed that there are different processes which cause an increase of chloroplast anchorage, on the one hand by an increase of plasmic viscosity and on the other hand by a phytochrome contolled increase of the activity of actomyosin-like filaments.