Influence of Ammonium on the Growth and Development of Suspension Cultures of Pauľs Scarlet Rose

Abstract

Abstract In this work as in previous studies from this laboratory it was demonstrated that the presence of a trace amount of NH 4 + (72.8 μmol) stimulated the growth of Pauľs Scarlet Rose on a defined medium containing NO 3 − (1920 μmol) as the only other source of nitrogen. A kinetic analysis of several growth parameters showed that the rate of increase of dry weight, fresh weight, cell number, and cell volume were greater during early stages of growth (days 0–8) when NH 4 + was provided. During later stages (days 8–14) this relationship between the two cultures did not hold. The cells provided NH 4 + continued to increase in fresh weight and cell volume, but the cells which were not provided NH 4 + had a greater rate of dry weight and cell number increase. These differences led to 14‐day‐old cultures which were approximately equal in dry weight and cell number but differed by a factor of 2 in fresh weight. The presence of NH 4 + speeded up the development and growth of the cells.