Brookhaven National Laboratory Report BNL-6548

Most studies of the effect of radiation upon plant development utilized external sources of irradiation. Where radioactive isotopes were used these were primarily applied in metabolic or cytological studies. The effects of these isotopes are similar to those produced by external irradiation, modified by such phenomena as specific localization, timing of irradiation, modified by such phenomena as specific localization, timing of irradiation, etc. The advent of tritium as a means of irradiation over very restricted areas has opened a new possibility in radiobiology. Many substances have been tagged with tritium and its application has been manifold (1). Tritiated thymidine has found special favor in studies where the labeling of DNA was the prime aim. It also serves as a means of specifically irradiating regions where DNA is being formed (2). Wimber (3) was the first to examine in detail the effect of tritiated thymidine on the development of the plant have not yet been studied. The purpose these experiments was to study the effect of nuclear irradiation on the formation and differentiation of the root of Zea mays