ALUMINUM TOXICITY: MICROCHEMICAL TESTS FOR INORGANICALLY AND ORGANICALLY BOUND PHOSPHORUS

Abstract

Barley plants were grown in culture solns. with and without Al. In sections of roots microchemi- cal tests were made for inorganic P with ammonium molybdate. The same reagent was used for organically bound P after removing inorganic P with 30% HNO3, and then freeing the organic P with 30% H2O2. Al was detd. by the alizarin reaction. Pronounced positive results were obtained for inorganic P and for Al in the roots from the Al culture soln. After washing with 30% HNO3 negative tests were obtained. The control roots gave a negative test for inorganic P. With the simultaneous disappearance of large amts. of inorganically bound P and of Al from the roots grown in the Al culture solns., coupled with the apparent lack of inorganic P in the control roots, it was inferred that P is bound with Al, thus causing a P deficiency for ordinary plant metabolism.