Improvement of Growth Regulator Formulation 



791 



cules must adsorb to the cuticle (10), dissolve in the cuticle, diffuse 

 through the cuticle, penetrate the ectopias! (plasmalemma), and pass 

 into the mesoplasm. Here the molecvdes may migrate by symplastic 

 movement (diffusion and protoplasmic streaming) to the vascular tis- 

 sues where, experience indicates, they move rapidly in the phloem. 

 Auxin (12), phenoxy compounds (4), dalapon (8), and some other 

 regulators apparently traverse this route. There is evidence that they 

 may also be actively absorbed from the phloem during the process 

 of rapid transport (5, 6). 



If 2,4-D is applied in solution as the acid, the pH is around 3.3. 

 As the molecules cross the ectoplast they probably dissociate partially 

 at the prevailing pH of 5 to 6. Entering the sieve tubes of the phloem 

 they are present in the assimilate stream at a pH of around 7.0; thus 

 dissociation must be almost complete. This dissociation process un- 

 doubtedly steepens the diffusion gradient and accelerates uptake. 



Table 3. MH formulations rated according to the amount of regrowth shown by 

 'Bermuda' grass cultures. 



Formulation * 



MH, diethanoleamine salt, in 95 per cent 



ethanol 



MH, diethanoleamine salt, in 5 per cent 



glycerine 



MH, diethanoleamine salt, in 5 per cent 



Triton B-1956 



MH, diethanoleamine salt, in 0.16 per cent 



benzene 



MH, diethanoleamine salt 



JV-acetyl MH 



MH, diethanoleamine salt, in 1 per cent 



KCNS 



MH technical 



MH, K salt 



MH, dodecylamine salt 



MH, Nasalt 



MH, Mn salt 



A''-caproyl MH 



MH, Mg salt 



MH, Zn salt 



./V-benzoyl MH 



MH, diethanoleamine salt, in 50 per cent 



glycerine 



MH, Al salt 



MH, Ca salt 



MH, Cu salt 



MH technical, no Vatsol 



2-Ethyl hexoyl MH 



JV-benzoyl MH, no Vatsol 



Control 



Necrosis, f 

 Per Cent 



85 



70 



95 



75 

 70 

 65 



60 

 60 

 60 

 60 

 60 

 60 

 40 

 40 

 40 

 30 



25 



25 



20 



10 



10 















Regrowth J 



None 



None 



Trace 



Very slight 



Slight 



Slight 



Slight 



Moderate 



Moderate 



Moderate 



Moderate 



Dense 



Dense 



Dense 



Dense 



Dense 



Mod. -dense 



Dense 



Mod. -dense 



Dense 



Dense 



Dense 



Dense 



Dense 



Flowering J 





 





 

 





 

 



+ 

 

 + 

 + 

 + 

 + 

 + 



+ 

 + 



+ 

 + 

 + 

 + 

 + 



* Spray applied March 22, 1950. MH was applied at 0.5 per cent active basis in 

 all instances. All solutions except those noted contained Vatsol OT at 0.1 per cent. 

 t Data taken May 24, 1950. 

 {Data taken July 11, 1950. = no flowers, + = some flowers present. 



