A Labile‐Bound Component of Phosphate in the Free Space of Sunflower Plant Roots

An experimental method is described by which it is possible to follow continuously the uptake and release of certain radioactive isotopes and the uptake of water by the roots of young plants. The method has been used in a study of the ion fractions related to the initial uptake of phosphate in the roots of sunflower plants. Two non‐bound fractions were identified: one which was leachable in distilled water and another which was released from the roots only by a bathing medium containing inactive phosphate. Experiments using conventional analysis technique corroborated the results obtained by the recording technique.