56 



MINERAL SALTS ABSORPTION IN PLANTS 



0-4- 



o 



5 10 15 20 25 30 35 

 c, m equiv./L 



I I ! 1 I 1 I 1 I I I 



O 0-1 0-2 0-3 0-4 0-5 



l/C 



I I I I — I I 1 I I I I I ' I I r I I I I 1 



O 0-5 10 1-5 2-0 



400 



Time, hr 

 Fig. 18. External concentration and salt absorption 

 a. Relation between external concentration and absorption of Rb+ by barley 

 roots plotted conventionally (O— O) as reciprocals ( x x) and as logar- 

 ithms (+ + ) (data from Epstein and Hagen, 1952); b. The nitrate concen- 

 tration of the nutrient medium at different times during the absorption of 

 salt by rye plants (redrawn from Olsen, 1950). 



