EFFECTS ON MITOSIS, GROWTH, DIFFERENTIATION 



967 



is slightly retarded (Pereira and Linskens, 1963). Similar chromosomal 

 changes induced by mercurials have not been reported, as far as I know, 

 for animal cells. The growth stimulation by auxin applied to Avena coleop- 

 tiles is inhibited by p-MB at 0.3 raM (Cleland and Bonner, 1956), but the 

 effects on auxin transport in sunflower stem section are complex in that 

 0.01 mM p-MB accelerates transport 125%, 0.1 mM depresses it 25%, and 

 1 mM blocks it completely (Niedergang-Kamien and Leopold, 1957). It is 

 not known if interference with auxin transport or action is involved in 

 growth inhibition. 



The structure-action relationships of mercurials acting on the sporelings 

 of the marine red alga Flumaria elegans, reported by Boney et al. (1959), 

 were believed to demonstrate the importance of lipophilicity and penetra- 

 tion (Table 7-25). The alkyl mercurials are often 200-300 times more toxic 

 than HgClg, the branched chain compounds being less toxic than the straight 



Table 7-25 



Lethal Concentrations for Plumaria Sporelings Exposed 

 TO Mercurials for 18 Hr." 



Mercurial 



HgCl, 



Hgl, 



Methyl-HgCl 



Ethyl-HgCI 



n-Propyl-HgCl 



n-Butyl-HgCl 



«-Amyl-HgCl 



Isopropyl-HgCl 



Isoaniyl-HgCl 



Phenyl-HgCl 



Phenyl-Hgl 



« From Boney et al. (1959). 



chain. Some correlation between potency and the distribution ratios be- 

 tween ether and water, and between methyloleate and water, was claimed, 

 but discrepancies exist. Similar relationships have been reported for certain 

 marine crustaceans (e.g., Artemia salina), but in others (e.g., Acartia clausi) 

 there is little difference in toxicity between the mercurials. Inasmuch as 



