AN ULTRAMICROELECTRODE FOR DETERMINATION OF INTRACELLULAR OXYGEN - LIGHT-IRRADIATION-INDUCED CHANGE IN OXYGEN CONCENTRATION IN AN ALGAL PROTOPLAST

An oxygen ultramicroelectrode was fabricated by pyrolysis of butane inside a glass capillary, followed by electrodeposition of Pt. The intracellular determination of oxygen in an algal protoplast (diameter, approx. 80-mu-m) with the ultramicroelectrode indicated that at a light intensity of 25 klx, the oxygen efflux from a single protoplast caused by the light reactions is approx. 5 . 10(-13) mol/s and that corresponding to the dark reactions approx. 1 . 10(-13) mol/s.