Dormancy Associated with Repression of Genetic Activity

Abstract

The buds of dormant potato tubers incorporate C14-labeled uridine into RNA and DNA at a limited rate. Rate of such synthesis is markedly increased after pretreatment of the tubers with ethylene chlorohydrin, a treatment which also breaks dormancy. RNA synthesis by the buds of nondormant potato tubers is inhibited by actinomycin D, and is hence of the DNA-dependent type. Chromatin of the buds of dormant potato tubers is almost totally incapable of support of DNA-dependent RNA synthesis, yet chromatin of nondormant buds of potato tubers is highly effective in the support of DNA-dependent RNA synthesis by added exogenous RNA polymerase. It is concluded that the genetic material of the buds of dormant potato tubers is largely in a repressed state, and that the breaking of dormancy is accompanied by derepression of the genetic material.