Influence of the Salt Common in Alkali Soils 

 upon the Growth of Rice Plant. IV. 



On the Antagonism between Potassium 

 and Magnesium or Calcium Ions, 



By 

 Koji Miyake. 



The antagonism between potassium and magnesium or 

 calcium ions is especially interesting as shown in the experiment 

 of Osterhout I} on wheat seedlings and of Loeb 2) on Fundulus. 

 In these experiments, it was shown that the toxicity of potas- 

 sium ion is antagonized by magnesium or calcium ions, though 

 calcium shows a more marked antagonism than magnesium. 

 Hence we have undertaken to prove this relation in the case of 

 growing rice seedlings, and accordingly we have made the 

 following experiments : 



I. Experiment with KC1 and MgCl 2 . 



The antagonism between potassium and magnesium ions 

 was established with the young seedlings of rice, about 25 mm. 

 high, which were grown in distilled water from seeds of almost 

 uniform size and specific gravity (1.185-1.200). Beakers of 

 about 5.5 mm. diameter and 7 cm. deep, each containing 30 cc. 

 of the culture fluids, used for the experiment, the seedlings being 

 placed in the solutions on March 7th (1913). Five seedlings 

 were grown in each culture in the green house and the eva- 

 porated water was supplemented with distilled water from 



1) Bot. Gaz., Vol. 45, p. 117 (1908) ; Vol. 48, Pp. 98-104 (1909). 



2) Amer. Journ. of Physiol., Vol. 3, p. 327 (1900). 



