Rate of Absorption of Various Salts hy Plant Tissue. 495 



external solution and the loss of turgidity of the tissue. The tissue discs in. 

 the other solutions remained turgid at the end of the experiment. 



Fig. 5. — Carrot in Solutions of various Nitrates of Concentration N/50. 



At the end of the experiment the reaction of the solution towards litmus 

 was examined. The calcium and zinc nitrate solutions were neutral to- 

 litmus ; whereas the potassium and sodium nitrate solutions were slightly acid^ 

 the aluminium nitrate was markedly acid. 



The same series of nitrates were used with potato. As with other series,, 

 the same difference in the relation of absorption and exosmosis as compared 

 with carrot is observable. The highest apparent exosmosis took place in the 

 case of calcium nitrate. The results obtained are shown in Table VII and 

 fig. 6. 



The reactions of the solutions towards litmus at the end of the experiment 

 were exactly the same as with carrot. The significance of this 'we shall 

 discuss later. 



4. Potassium Salts. — The results obtained with chlorides, sulphates, and 

 nitrates indicate that the potassium ion is absorbed more rapidly than the 

 other metallic ions used in these experiments. As, for the reasons we have 

 given in a former paper, the values for absorption obtained by the conduc- 

 tivity method give approximately the intake of the less absorbed ion, in 

 comparing the absorption of anions, we have chosen potassium salts, as the 



