Chloroplast RNA: possible site of an early lesion in iron deficiency

Euglena gracilis was grown under controlled levels of iron suchthat chlorophyll synthesis was halted, although the cells continuedto grow at a normal rate. Chloroplasts isolated by zonal centrifugationfrom iron-deficient cells, even at a very early stage of deficiency,contained less than half the normal levels of RNA and ribosomes.Total RNA was unaffected. We note that a defect in chloroplastribosomes could account for the signs of iron deficiency chlorosis. ¹Present address: Forschungsstelle Vennesland der Max PlanckGesellschaft, Harnackstr. 23, Berlin 33, Dahlem, Germany. (Received April 16, 1974; )