AUTORADIOGRAPHY 



345 



removed with xylene, and the sHdes hydrated, photographically proc- 

 essed, and stained with Dolafield's hematoxylin. 



Metabolic. Trayislocation. Figure 7-12 shows the translocation pat- 

 tern of Fe*^ injected into the stem of the peanut plant (courtesy of 

 D. Davis). The site of injection is indicated by A . The stem above and 

 below the region of injection was cut so that as much plant material as 



(a) {b) 



Fig. 7-11. Median longitudinal section of terminal millimeter of a root [(X50) (a), 

 (X80) (6)]. Note concentration of C^'* in the inner cortex A, outer stele B, and 

 superficial cells C. Probable path of translocation is indicated by D. [From G. S. 

 Rabideau and Leo W. Mericle, The Distribution of C^* in the Root and Shoot Apices of 

 Young Corn Plants, Plant Physiol., 28: 329-333 (1953).] 



possible could be placed on the film. As shown by B, the leaves, petioles, 

 and stem below the site of injection exhibited little darkening, thus indi- 

 cating that there had been relatively slight downward movement of the 

 Fe*^. It will be noted from the stem above the site of injection (C, D) 

 that considerably more translocation occurred along the left-hand side of 

 the stem. This undoubtedly resulted from the mechanics of injection 

 and is also reflected in the fact that the leaves on the left showed higher 

 concentrations than those on the right. It was also noted that the petiole 

 bearing leaves E showed a higher concentration on the left; this was 



