Oct. 1918.] 



K MIYAKE.— INFLUENCE OF THE SALTS ETC. 



199 



dually is poisonous, the toxic effect of these ions is almost 

 mutually counteracted and a medium is produced in which the 

 plant may live almost indefinitely. The toxic effect of sodium 

 ion has almost completely disappeared when we added a little 

 calcium ion ; on the other hand, the poisonous effect of calcium 

 ion was excluded by the addition of a great amount of sodium 

 ion. 



IV. Experiment with MgCl 2 and CaCL. 



On July 20th (1912), 30 seeds of rice which were almost 

 uniform in size and specific gravity (1.185—1.200) were sown 

 in beakers of about 5.5 cm. diameter and 7 cm. deep, each 

 containing 30 cc. of 1/10 N. CaCL, 25 cc. of 1/10 N. CaCl 2 + 5 cc. 

 of 1/10 N. MgCl,, 20 cc. of 1/10 N. CaCL + 10 cc. of 1/10 N. MgCl 2 , 

 15 cc. of 1/10 N. CaCl 2 + 15 cc. of 1/10 N. MgCl, 10 cc. of 1/10 

 N. CaClA 20 cc. of 1/10 N. MgCl 2 , 5 cc. of 1/10 N. CaCl+25 cc. 

 of 1/10 N. MgCl and 30 cc. of 1/10 N. MgCl respectively. The 

 beakers were kept in room temperature and covered with glass 

 plates to exclude dust and retard evaporation until the seed- 

 lings reached a height of about 15 mm. The evaporated water 

 was supplemented with distilled water from time to time to 

 keep the culture mediums always in their initial concentrations. 

 The difference in the development of the plants became very 

 marked. On August 20th, the plants were measured, and the 

 results obtained are shown in the following table : 



Solutions used 



Length 

 of leaf 



Length 

 of root 



Number 

 of roots 



1/10 N. CaCL 30 cc. 



mm. 



35 



mm. 



8 



1 



1/10 N. CaCL 25cc. + l/10 N. MgCL 5 cc. 



55 



5 



2 



1/10 N. CaCL 20cc. + l/10 N. MgCl 2 10 cc. 



80 



6 



5 



1/10 N. CaCL 15cc.+l/10N. MgCl 2 15 cc. 



95 



25 



4 



1/10 N. CaCk lOcc + 1/10 N. MgCl 2 20 cc. 



105 



22 



5 



1/10 N. CaCL 5cc. + l/10 N. MgCL 25 cc. 



110 



40 



8 



1/10 N. MgCl 2 30 cc. 



45 



5 



1 



