﻿BOTANICAL GAZETTE 



Experiments and results 



In order to determine the relative toxicity of these various 

 solutions to Tradescantia, cuttings of the plant were placed in 

 various dilutions of each solution with redistilled water. In this 

 way the percentage of the solution (that is, the number of cc. 

 diluted to 100 with redistilled water) that would allow the forma- 

 tion of roots but inhibit the production of root hairs was determined. 



All of the solutions except 5A were acid to both litmus and 

 phenolphthalein. Their acidity was determined by titrating with 

 N/10 NaOH, using phenolphthalein as an indicator. 



Table I gives the toxic limits of these solutions to Tradescantia 

 (as previously denned) and their acidity, together with the relative 

 rank of each solution as to toxicity and acidity and the ratios of 

 these. 



TABLE I 



1AN25/K 

 iB N24/1C 

 'CN.i/k 



All of the solutions mentioned in table I, except 3B, were 

 neutralized to phenolphthalein with N/10 sodium hydrate, and 

 the effect of both the acid and the neutral solution was tried on 

 Tradescantia cuttings. Table II shows the results of the dilutions 

 named on Tradescantia cuttings. 





(|« e cfnt) 







iB 



iC 



7-5 



7-5 

 60.0 



Root hairs none 

 '* || slightly stunted 



Roots none" 0 " 6 



Root hairs normal 



" " normal ^ ^ 



Roots 3-10 mm. font: 

 Root hairs slightly stunted 



2B 





