DISTRIBUTION STUDIES OF RADIOACTIVE FLUORINE-18 AND STABLE FLUORINE-19 IN TOMATO PLANTS

Abstract

A study of distribution and site of accumulation of fluorine in tomato plants was carried out using NaF/sup 18/, HF/sup 18/, NaF/sup 19/, and HF/sup 19/ applied as solutions through roots and cut vascular systems, and in gaseous form to the aerial parts. In order of decreasing concentration, the gross distribution of fluorine applied as NaF/sup 19/ through the soil was: roots, lower leaves, upper leaves, and stems. Regardless of the path of entrance of the fluorine into the plant, it was possible to wash up to 68 per cent of the fluorine from the leaves with distilled water and up to 83 per cent with water containing a detergent (Tween #20). Distribution based on autoradiograms showed that most accumulation of F/sup 18/ applied as HF/sup 18/ to tomato plants was at the tips and margins of leaflets and in the glands along the stem. Little F/sup 18/ was found in the stems and petioles. In short-term or long-term experiments up to 8O per cent of the F/sup 18/ or F/sup 19/ of the leaves applied as HF was found in the stripped epidermis of Sedum spectabile Boreau. Distribution of F/ sup 19/ applied as H/sup 19/ to tomato leavesmore » after long-term accumulation was, in order of decreasing concentration: cell walls, chloroplasts, soluble proteins, mitochondria, and microsomes. With short-term accumulation of F/sup 18/ applied as HF/sup 18/ the order was: soluble proteins, chloroplasts, cell walls, and mitochondria. The fluorine in the chloroplasts was associated mainly with the proteinaceous substances since little or no F/sup 19/ was found in the pigments and lipids. (auth)« less