Uptake of 14C-L-Glutamic Acid by Daucus carota Cell Suspension in Different Shock Situations

Cell suspension cultures of Daucus carota were shocked by inoculation or by temperature, salts or osmotica in combination with inoculation. Changes in cell vitality were measured by uptake studies with labelled L-glutamic acid performed during the first 30 min after shock treatment. The cell sample was then collected on filter and counted in a liquid scintillation counter. Inoculation alone caused a marked decrease in uptake. Normal uptake capacity was re-established within 2 h. Temperatures of 0?20°C as against 27°C gave an additional decrease in uptake. Of the tested osmotica, polyethylene glycol gave the greatest stabilizing effect on the glutamic acid uptake and sucrose the least. The highest uptake rates were obtained with a calcium concentration of 0.10–0.15 mM.