Rate of Absorption of Various Salts by Plant Tissue. 489 



From the Table and curves it will be observed that, in the first place, the 

 apparent rate of absorption differs greatly with the different salts, and also 

 that the initial rate does not depend on the position of equilibrium. There is 

 little doubt that after 91 hours equilibrium is practically attained. 



:0 20 so 40 50 60 70 60 90 



TIME IN HOURS 



Fig. 1. — Carrot in Solutions of various Chlorides 6f Concentration N/50. 



In N/50 solutions the four salts employed have almost identical ionic 

 concentration, so that the difference in the rates of intake cannot be accounted 

 for on the ground of differences in concentration. In Table II are given the 

 degree of dissociation (which is proportional to the ionic concentration), and 

 the mobility of the kation and the coefficients of diffusion in the case of the 

 four salts. These physical constants are those given by Landolfc and 

 Bornstein (3). 



Table II. — Absorption of Chlorides by Carrot. Mobility of Anion 654. 



Salt. 



Degree of 

 dissociation. 



Mobility 



of 

 kation. 



Coefficient 

 of diffusion. 



Decrease in 

 conductivity 

 after 1 hour. 



Decrease in 

 conductivity 

 after 18 hours. 



Lithium chloride ... 



91 



33 -4 



0-70 



67 



257 



Sodium chloride 



91 



43 -6 



0-94 



80 



550 



Calcium chloride ... 



85 



51-8 



0-68 



113 



176 



Potassium chloride 



92 



64 -7 



1 -36 



175 



750 



This Table suggests that the initial rate of salt absorption is dependent on 

 the mobility of the kation. This result falls into line with the results 

 obtained for hydrogen chloride (11). The mobility of the hydrogen ion is 



