«()() 



A. S. Crafts 



'.V; ( 





h 



S 



2 Days 



4 Days 



8 Days 



Fig. 9. Same as Figure 7, treatment times 2, 4, and 8 days. 



Next to move to the tops, in order of appearance are: amitrol and 

 PO4 in 4 hrs.; by 8 hrs. dalapon, lAA, and MH; after 2 days 2,4-D 

 at very low concentration; after 4 days urea, or some compound carry- 

 ing its Ci^. 



After 8 days, concentrations in roots from high to low are in the 

 following order: PO4, lAA, simazin, monuron, amitrol, 2,4-D, MH, 

 dalapon, urea. In tops the order is simazin, monuron, amitrol, PO4, 

 dalapon, MH, lAA, 2,4-D, and urea. Figures 7, 8, and 9 show the re- 

 sults of this experiment. 



Formulation of soil-borne chemicals usually aims at solubility as 

 related to penetration and leaching, at particle size as related to rate 

 of solution, at pelleting as a means of distribution and of selectivity, 

 and at pellet composition as related to partitioning. 



From these various observations it seems that formulation holds 

 much promise for obtaining maximum usefulness of regulator mole- 

 cules. Synthesis and screening arc fmnishing new compounds and 



