Asynchronous Synthesis of RNA in Nucleoli of Root Meristem

Abstract
During pulse incubations of onion roots with RNA precursors, incorporation into meristematic nucleoli is asynchronous for some, but not for all, cells. After a 30-minute labeling period, the "zero-class" is as large as 25 percent, and the asynchrony is intracellular rather than cellular. This suggests an individual specificity of nucleolar function in a population of differentiating cells.