270 



THE BOTANICAL MAGAZINE. 



[Vul. XXVII. No. 



II. Experiment with KC1 and CaCl 2 . 



The antagonistic action of potassium and calcium ions on 

 each other was examined with potassium and calcium chloride 

 in the same manner as in the first experiment. The result 

 obtained was as follows : 



Solutions used 



Length 

 of leaf 



Length 

 of root 



Number 

 of roots 



1/10 N. KCl 30 cc. 



mm. 



40 



mm. 



17 



3 



1/10 N. KCl 25cc. + l/10 K CaCl % .5 cc. 



68 



51 



10 



1/10 N. KCl 20cc.+ l/10 N. CaCl 2 10 cc. 



65 



25 



8 



1/10 N. KCl 15cc. + l/10 N. CaCU 15 cc. 



65 



25 



8 



1/10 N. KCl 10 cc. + 1/10 N. CaCk 20 cc. 



65 



25 



8 



1/10 N. KCl 5 cc. + 1/10 N. CaC% 20 cc. 



64 



20 



8 



1/10 N. CaCl 30 cc. 



35 



18 



3 



Distilled water 30 cc. 



63 



47 



11 



As will be seen from the above table, even in this case, a 

 result was obtained, similar to that of previous experiment. 

 But it is clear that calcium has a more marked antagonistic 

 action than magnesium and decidedly prevents the toxicity of 

 potassium ion. 



Result. 



Potassium and magnesium or calcium salt are poisonous 

 to rice plant when used separately but when mixed together 

 (in suitable proportion) the poisonous effect more or less com- 

 pletely disappears. The results coincide with those of Oster- 

 hout and form an important factor in the question of soil 

 fertility. 



Chemical Laboratory, College of Agriculture, 



Tohoku Imperial University, Sapporo, Japan. 



July 1913. 



