THE CONSTITUENTS OF THE ASH OP PLANTS 179 



its molecule. It is probably an indirect effect arrived at 

 through faulty nutrition set up in the absence of the metal. 



4 3125 



FIG. 89. PLANTS OF BUCKWHEAT CULTIVATED IN VABIOUS NUTRITIVE 

 SOLUTIONS. 



1, normal solution containing all necessary salts; 2, solution containing the same 

 salts as 1, except potassium compounds ; 3, solution of same composition as 1, 

 except that sodium salts have been substituted for potassium compounds ; 4, 

 solution of same composition as 1, except that no calcium salts are present; 

 5, solution containing no compounds of nitrogen. 



At first sight it seems as if the absence of inorganic salts 

 may be effective by interfering with the maintenance of the 

 turgid condition of the cells, as all the compounds men- 

 tioned have osmotic properties. It is evident, however, 



12* 



