Rice and bean plants were grown in nutrient solution in the presence of three levels of N, P and K. The method of the bioevaluation of the nutricional status, in which excised roots are allowed to take up tagged elements, in this case 15N and 32P, was compared with foliar analysis. Two main conclusions were drawn: 1) the bioevaluation proved to be an useful and rapid procedure for the diagnosis of the nutricional status of both species, since there was a significant negative correlation between absorption of N and P and dry matter yield; 2) the uptake of the tagged ions with either element by the roots of plants grown under deficient levels of N and P in the nutrient solution was inversely proportional to the leaf concentration of both nutrients.
nutricional status; bioevaluation; rice; bean; 15N; 32P