THE UPTAKE OF PHOSPHORUS BY BEAN PLANTS WITH PARTICULAR REFERENCE TO THE EFFECTS OF IRON

This paper presents some of the findings of a study of the uptake of phosphorus by bean plants as it is influenced by iron. As a result of this work a number of points have been brought out which have not been clearly stated previously. In order to complete the study successfully, the effects of pH and the simultaneous effects of various phosphorus and iron supplies were considered. The results show: (a) Absorbed iron ties up a portion of the " seed phosphorus " in an unusable condition, (b) A ferric phosphate precipitate, in or on the roots, retards the flow of phosphorus to the actively growing leaves, (c) As the phosphorus content of the nutrient medium is increased, roots, stems, and cordate leaves continue to build up in phosphorus content even after trifoliate leaves are being adequately supplied. The excess phosphorus may be responsible for immobilizing iron and other ions.