A reversible growth inhibition of isolated tomato roots

Introduction. - It is known that certain bacteria are inhibited in their growth by the presence of sulfanilamide or related compounds in the nutrient medium, and it has been suggested by Fildes(1) and by Woods(2) that this inhibition is due to specific interference with the utilization of essential metabolites, in particular p-amino benzoic acid. In the present paper data will be presented which show that the growth of isolated tomato roots(3) is inhibited in the presence of appropriate concentrations of sulfanilamide or its derivatives, but that this growth inhibition can be in whole or in part abolished by the further presence of p-amino benzoic acid, a substance not otherwise essential as a supplement for the growth of isolated tomato roots.