90 



MINERAL SALTS ABSORPTION IN PLANTS 



but a capacity to do so develops if they are washed for a time in an 

 aerated sokition of salt or in aerated distilled water (see Fig. 4 p. 16, 

 and Fig. 22b, p. 66). The development of absorptive ability has 

 been attributed to synthesis or activation of carrier molecules 

 resulting from enhanced metabolism induced by this treatment 

 (Sutcliffe, 1954b). It has been observed (Fig. 32b) that chloram- 

 phenicol inhibits this process, and disks washed for 48 hr in a 



■a 



£1 

 D 



3 



cr 



1-234 



Time, days 



Fig. 32 (b). Effect of chloramphenicol on salt absorption 

 b. Uptake of potassium ions by red beet disks, washed for about a day in 



water, and then transferred (a) to 0-01 M potassium chloride (H h) (b) to 



distilled water for 2 days, and then 0-01 M potassium chloride (H h) (c) to 



0-01 M potassium chloride + chloramphenicol (2g per 1) (O— O) and (a) to 



chloramphenicol (2g per 1) for 2 days, and then transferred to 0-01 M 



potassium chloride, at 25 °C (from Sutcliffe, 1960). 



solution of the antibiotic behave as if they are freshly cut. The 

 respiration rate is lower than that of similar disks washed in water, 

 and chloramphenicol evidently inhibits some metabolic activity 

 (perhaps the synthesis of protein), upon which both enhanced 

 respiration and the stimulation of ion absorption depend. 



C. Salt Absorption and Organic Acid Metabolism 



Hoagland and Broyer (1936) noticed that after barley roots had 

 absorbed salt from a solution of calcium bromide, the expressed 



