122 



BOTANICAL GAZETTE 



[FEBRUARY 



TABLE VI 



Wheat 



CULTTTRE SOLUTION 

 QUANTITIES IX CC- 



Gro\\'th during 6o days 

 aggregate length of roots per plant ix mm 



In .09377n solutions 



KCl 



loo KCl 



lOO MgCla 



loo KCl 

 so MgCU 



looKCl 



25 MgCU 



MgCl. , 



50 K,S04 

 50H2O 



50 K,S04 

 100 MgS04 



SO K.SO^ 

 50 MgSO^ 



50 K2SO4 

 25 MgSO^ 



MgSO^ 



KKC. 



100 KNO3 



100 Mg(N03)2 



100 KXO3 



5oMg(N03). 



looKNOg 

 25 Mg(N03), 



Mg(N03). 



Distilled water 



In -0375 m solutions 



268 



170 



224 



340 



220 



312 



20 



2X6 



112 



294 



28 

 276 



144 



148 



166 



10 



76 



190 



144 



224 



S 



240 



24 

 345 



104 



198 



290 



10 



740 



Since each moleciile 01 K..SO4 yields two K ions, half as much K,S04 is used as KCl or KNOj. 

 The figures ior 50 KaSO^-t-so HaO are comparable with the corresponding figures for KCl and K>.03, 

 though the concentratioa of the solution is only half as great. For example, the roots reach a length 

 of &c^^ in 5o« K,SO* .0937 m-^- 50'"' HaO; a length of 216'"'^ in 50== K.SO* -05 m + so" H>0; and 

 a length of 276=^ in 50** K,S04 .037SW+-so" H,0. 



It wiU be noticed tiiat these antagonistic effects are less marked as 

 the concentration is lowered. This is of course true of all antago- 

 nistic action, sin<x as the concentration is lowered toxicity diminishes 

 and the effect of its inhibition is consequently less striking. 



It is olBer\'ed that those parts which are in direct contact with 

 solutions always show their effects much more plainly than those 



