Differential Effect of Phosphate Starvation on the Rates of Cell Division and Plastid Replication in Euglena*

SYNOPSIS. The effects of phosphate starvation on the synthetic and division rates of Euglena gracilis strain Z are described. Phosphate starvation inhibits rates of the following processes, in the order: RNA synthesis > DNA synthesis > cell division > chlorophyll synthesis and plastid replication. As a consequence of the differential effect of phosphate starvation on the synthetic and division rates the average gross chemical composition of the cells is subject to continuous change.