ISO 



Plant Tissue Cull me 



Pig. \'.k Excised tomato roots grown in solutions containing, in 

 addition to other essentia] constituents, the following concentrations 

 of Fe.,(S0 4 ) 3 , reading from Left to right: none, 0.6, L.8, 6.0, 18.0, 

 ;mil 60.0 • Ki " M. Photograph was taken after cultivation for one 

 week. (From White, P. E. 1942. Planl Physiol. 17: L58, fig. 4, 

 37.) 



