Permeabilizing soybean protoplasts to macromolecules using electroporation and hypotonic shock.

The percentage of soybean cell culture protoplasts permeabilized by electroporation was dependent on the voltage and the number of successive pulses that were applied. Best results were obtained with two 50 milliseconds, 400 volts per centimeter pulses after which 78% of the surviving protoplasts had been permeabilized to the fluorescent dye calcein. Quantitation of the volume of extracellular fluid taken up was performed using radioactive inulin (molecular weight 5000-5500). Typically between 20 and 40 nanoliters of fluid was taken up by 10(6) protoplasts. Electroporation and hypotonic shock treatments (M Saleem, AJ Cutler 1986 J Plant Physiol 124: 11-21) were compared with respect to the volume of fluid taken up under optimum conditions. Electroporation produced 10 times more uptake than hypotonic shock treatment. In all experiments there was a direct relationship between the number of protoplasts lysed and both the amount of fluid taken up and the percentage of surviving protoplasts that were permeabilized.