FACTORS AFFECTING SALT ABSORPTION 



53 



300 



5 240 



Time, hr 



60 



■-^ 



•| 40 

 a> 



oT 20 



-iO-0026 



0-0018 



0-0010 



c 

 o 

 u 

 I 1^ 

 o 



pH 



Fig. 17 (a-b). pH and salt absorption 

 a. Absorption of K^( — ) and Cr ( — ) by washed red beet root slices at 

 25 °C from 0-0024 M. potassium chloride solutions buffered at pH 6 (D) and 

 pH 8-5 (O) (redrawn from Hurd and Sutcliffe, 1957); b. Absorption of K+ 

 by washed red beet root slices in 6 hr at 25 °C from 0024 M. potassium 

 chloride solutions at different pH values (O — O); and the theoretical) 



amounts of HCO3 retained in solution under the same conditions ( ) 



(redrawn from Hurd and SutcHffe, 1957) 



In solutions which were freed of bicarbonate ions the amount of 

 nitrate absorbed was found to be independent of pH values between 

 4 and 9. Van den Honert and Hooymans (1955) demonstrated that 

 uptake of nitrate by maize plants decreases with increasing pH value 

 (Fig. 17c), and concluded that hydrogen ion concentration rather 



5 M.S.A.P. 



