Tracer Technique used in Examination of Activity of Roots of Grass Swards

Abstract

THE interpretation of measurements of the uptake by plants of tracer isotopes from the soil is complicated by at least three factors. First, exchange takes place between the added labelled ions and the isotope ions present in the soil; the rate of this exchange has been shown to be affected by many factors^1,2. Secondly, continuous exchange occurs between the nutrient ions in the roots and those in the soil^3–6. The factors controlling this exchange are unknown. Thirdly, there is the possibility of damage to plant tissues, resulting from accumulation of the tracer. Although a number of experiments have shown no appreciable effects of radiation in terms of yield of dry matter^9–12 and uptake^9,12, the question of radiation damage to plant tissues in long-term uptake experiments remains unsettled. Critical studies^13,14 have shown that even very low doses of radiation may produce some physiological changes in plant cells.