46 



ELECTROLYTES IN BIOLOGICAL SYSTEMS 



after removal of the inhibitor from the environment, the cell can tend to restore 

 the normal levels of sodium and potassium. To elucidate this point, samples of 



POTASSIUM 



UJ 



O 35 



o 

 o 



♦^ 30 



s 



5 



0.002 M lA" and LIGHT 



25 



10 



15 20 



-HOURS- 



35 



Fig. 6. Loss of potassium in the dark from Ulva previously treated with 0.002 m/1. iodo- 

 acetate in the light. The arrow indicates time of transfer of six samples to inhibitor-free sea 

 water and darkness. 



15 20 



-hours- 



Fig. 7. Gain of sodium in the dark from Ulva j^reviously treated with 0.002 m/1. iodoace- 

 tate in the light. The arrow indicates the time of transfer of six samples to inhibitor-free sea 

 water and darkness. 



Ulva were maintained in o.ooi m/1. iodoacetate in the dark for 16 hours, then 

 placed in running sea water (no inhibitor) in the light. 



After 16 hours in the iodoacetate, approximately 30% of the cellular potas- 

 sium is lost, and a progressive loss, amounting to an additional 50% of the origi- 



