Further studies on the relationship between the rates of nitrate uptake, growth and conductivity changes in the medium of plant cell suspension cultures

摘要

The changes in packed cell volume and in nitrate content and conductivity of the medium during the growth cycle of cell suspension cultures fromPetroselinum hortenseHoffm.,Glycine maxMerr., andHaplopappus gracilisA. Grey in a chemically defined medium were compared. In all three cases sigmoidal curves obtained for large decreases in the conductivity were paralleled by similar curves for the rates of nitrate depletion from the medium until this nutrient was completely exhausted. Further decreases in the conductivity subsequent to nitrogen starvation proceeded at relatively slow rates and ceased when the cultures entered into the stationary phase of the growth cycle. Thus the previously reported method of deriving growth curves indirectly from conductivity measurements (Hahlbrock and Kuhlen, Planta108: 271–278, 1972; Hahlbrocket al., Planta118: 75–84, 1974) might be generally applicable for this particular medium. The method seems to be based on a continuous uptake by the cells of ionic constituents throughout all stages of actual growth, even beyond the stage of nitrate exhaust