2l6 



Mineral Nutrition of Plants 



\ 2 3 4 S 6 7 8 9 10 I 1 1 2 I 3 I 4 1 5 16 I 7 16 19 20 21 



Figure 17. Differential accumulation of cations by various species of 

 plants. Equivalent percentages of Na, K, and Rb in plants containing 

 these cations in equivalent amounts. The plants are arranged according 

 to increasing Na content. 



The plants were cultivated in a solution: 2 NaNO :j -|- 2 KH.,P0 4 -f- 

 2 RbCl -f 2 MgS0 4 -f 2 Ca(NO,), + 0.0 1 MnCL + an unknown 

 amount of Sr. In preparing the solution, 0.0005 milligram equivalents 

 SrCl, per liter of solution was intentionally added; the Ca salt used prob- 

 ably contained some Sr. The figures preceding the chemical formulas give 

 the milligram equivalents per liter of solution. — Collander ( 18) 



