Changes in RNA-Synthesizing Activity and Template Activity in Nuclei From Cotyledons of Developing Pea Seeds

Abstract

Using Pisum sativum grown under controlled conditions, the pattern of cotyledon development has been defined in terms of fresh and dry weight, number of cells, and content of chlorophyll, starch, DNA, RNA and protein. The onset of storage-protein synthesis has been determined using antibodies to purified vicilin and legumin. During growth by cell expansion, DNA per nucleus of the parenchymatous cotyledon cells increases to an average of 50 C. Measurements of the endogenous RNA polymerase activity of nuclei and the template activity of chromatin isolated at various stages during seed development, suggest that the DNA beyond 2 C level does not contribute in a major way to RNA synthesis, although its template activity per unit of DNA is not diminished.