INFLUENCE OF THE ALKALI SALTS UPON THE GROWTH OF RICE PLANTS. 253 
As seen in the above table, both results almost coincide in the toxic 
and stimulating point. A slight fluctuation of the stimulation point is 
probably due to the fact that the plant growth varies, to a certain extent, 
with the temperature and other factors, since these experiments were not 
carried on at constant temperature and under identical conditions. 
The influence of the salts under our examination upon the growth of 
young seedlings, have been studied by many investigators. In 1887, 
Hindolf 0 observed a good influence of magnesium and calcium chloride 
upon the early development of many cultivated plants. C o u p i n s) studied 
the toxic influence of many salts upon the growth of the young root of 
wheat, and found that calcium chloride was toxic in concentration of 1/200. 
Hebert 3 ' also investigated the toxicity of chromium, aluminium and 
magnesium salts upon the growth of germinated seeds of wheat and rape 
and observed that the toxic action of magnesium salt was least among 
these salts and often harmless. An elaborate investigation of the toxic 
concentration of various alkali salts upon the growth of seedings of many 
plants has been made specially by Kearney and Harter 0 . Their re- 
sults are shown in the following table. 
Critical concentration of pure solutions. 
Salts 
Plants tested 
used 
White- 
lupine 
Alfalfa 
Wheat 
Maize 
Sorghum 
Oats 
Cotton 
Beet 
I 
II 
MgS0 4 
0.001 25N. 
0.007 
N. 
±0.001 N. 
0.005 N. 
0.25 N. 
1 
0.00375N. 0.001 875N. 
0.0003 1 2N. 
0.0005 N. 
MgCl 2 
0.0025 „ 
0.0075 
99 
±0.002 „ 
0.005 11 
0.08 „ 
0.00125 „ 
0.001875 „ 
0.0004 ii 
0.0005 ). 
Na 2 C0 3 
0.005 „ 
0.0125 
99 
0.0125 n 
0- 0I 5 11 
0.00675 „ 
0.00625 ,, 
0.005 
0.00625 „ 
Na 2 S0 4 
0.0075 „ 
0.04 
1) 
0.04 „ 
0.05 „ 
0.0125 „ 
0.0175 „ 
0.005 „ 
0.00875 .1 
NaCl 
0.02 „ 
0.045 
99 
0.045 
0.04 ,, 
0.015 „ 
0.02 „ 
0.00625 „ 
0.025 „ 
NaHCQ 3 
0.02 „ 
0.03 
99 
0.025 „ 
0.05 „ 
0.00875 „ 
0.0075 » 
0.00625 „ 
0.0075 » 
1) . Hindolf,— I.e. 
2) . C o u p i n, - 1. c. p. 645. 
3) . Hebert,— Bull. Soc. chim., France, 4, Ser. 1, 18. p. 1026 (1907); Jahresber. Agrikchem., 
11 p. 252 (1908). 
4) . Kearney and Harter, — Bull. No. 113, Bureau of Plant Industry, U. S. Dept. of 
Agriculture (1907). 
