Rate of Absorption of Various Salts by Plant Tissue. 491 



Table III. — Potato in Solutions of various Chlorides of Concentration N/50. 



Potassium chloride. 



Sodium chloride. 



Lithium chloride. 



Calcium chloride. 



Time 



Change in 



Time 



Change in 



Time 



Change in 



Time 



Change in 



in 



electrical 



in 



electrical 



in 



electrical 



in 



electrical 



hours. 



conductivity. 



hours. 



conductivity. 



hours. 



conductivity. 



hours. 



conductivity. 



0-5 



-116 



0-5 



- 87 



0-5 



- 33 



0-5 



- 70 



3 



-115 



3 



- 61 



3-0 



- 23 



3-0 



- 45 



24 -25 



- 45 



24 -4 



+ 66 



24-5 



+ 150 



24-12 



+ 136 



45-25 



+ 40 



45-5 



+ 190 



45 -5 



+ 314 



45-12 



+ 219 



400 



2 4 6 P It 20 40 - 50 



TIME IN HOURS 



Fig. 2. — Potato in Solutions of various Chlorides of Concentration N/50. 



2. Sulphates. — The salts employed in this series were the sulphates of 

 potassium, sodium, magnesium, zinc, and aluminium. The first three are 

 nutrient or harmless salts, zinc is generally regarded as a toxic element, 

 while the anomalous behaviour of aluminium has been discussed in an earlier 

 paper (12). 



The results are such as might be expected. The greatest apparent absorp- 

 tion takes place with potassium sulphate, less with sodium sulphate, and 

 still less with magnesium sulphate. With zinc and aluminium sulphates 

 the electrical conductivity of the solution increases with continued immer- 

 sion of carrot tissue in it. It will be observed tliat in the case of zinc 

 sulphate a decrease in conductivity takes place during the first half hour 

 corresponding to an absorption of the salt. Subsequently, the conductivity 

 rises and continues to do so until the end of the experiment. This behaviour 

 is completely explained on the basis of the absorption of the zinc ; its toxic 



