Preparation of Radioautographs to Show the Distribution of Phosphorus-32 in Plant Tissues

Abstract

PELC¹ has developed a radioautographic technique to show in microscopic detail the accumulation of iodine-131 in the thyroid gland. A thin 'stripping' photographic emulsion is floated on to the tissue sections mounted on a glass slide. The precision with which the tracer can be located within the tissue depends not only on the thinness of the section and the emulsion but also on the closeness of contact between them. In applying this method to the study of the distribution of phosphorus in plant tissues the following complications arise : (1) a considerable diffusion of phosphorus occurs in the fixatives normally used ; (2) the time required to prepare sections by standard plant histological methods is so long that much of the tracer decays before the radioautograph can be exposed.