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

Abstract

In this work as in previous studies from this laboratory it was demonstrated that the presence of a trace amount of NH4+ (72.8 μmol) stimulated the growth of Pauľs Scarlet Rose on a defined medium containing NO3− (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 NH4+ was provided. During later stages (days 8–14) this relationship between the two cultures did not hold. The cells provided NH4+ continued to increase in fresh weight and cell volume, but the cells which were not provided NH4+ 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 NH4+ speeded up the development and growth of the cells.

Influence of Protein Synthesis on NO3− Reduction, NH4+ Accumulation, and Amide Synthesis in Suspension Cultures of Paul's Scarlet Rose

“…Inasmuch as the ratio of fresh to dry weight changes during growth (18), the H20 content of cells at each age was determined by subtracting the dry weight (18) from the fresh weight at each age. These H20 values were used to calculate the mm concentration of NH4' at each age by assuming that the NH4+ was evenly distributed throughout the cell, which is highly unlikely.…”

“…Cultures were initiated in both types of medium by inoculation with 0.5 g of cells from 14-day-old N03 + NH4+ cultures. Because of differences in the growth rates in the two media (17,18) cells were grown for 14 days in the NO3 + NH4+ medium and for 21 days in the N03 medium. At regular intervals during the growth cycles, 1-to 15-g samples ofcells were harvested and homogenized in 80% ethanol with a Blackstone Ultrasonicator set at 80%Yo of full power for 2 min.…”

Changes in protein and protease activity during the growth and senescence of Paul's Scarlet rose

“…Cultures were grown on MPR medium, and harvested as previously described [5,6]. From each harvested culture, 600 mg of cells was used immediately for the protease assay, and 250 mg was stored at 5 °C in dilute HC1 for subsequent cell counting and size determinations [5]. Fresh weights were obtained on the remaining tissue, which was then dried at 80 °C for 48 h and reweighed to determine the dry weights.…”