Lecture 6 — 127 — Biochemical Problems 



ism of the intake of the salt with the energy for this 

 process provided by the respiration that would take 

 place in the absence of potassium in the external solu- 

 tion. Some potassium absorbed during the growth 

 period of the plant would of course already be present 

 in the tissue and so could serve the indispensable pur- 

 pose of this element in metabolism. A similar ques- 

 tion would arise concerning any other ions. 



Whatever view may be taken of this particular 

 aspect of the phenomena, it is significant that in 

 storage tissues and in roots the absorption of certain 

 salts leads to an increase in respiration as denoted by 

 CO2 production or oxygen consumption. Steward 

 suggests that ions or salts with the capacity to bring 

 about this stimulation are most effective during their 

 actual passage into the living cells. 



One point should be made clear concerning the 

 influence of salt absorption on respiration in view of 

 recent discussions. There appears to be no disagree- 

 ment among investigators in this field as to a salt 

 effect on respiration by roots and storage tissues. The 

 divergence of views has to do with the nature of the 

 effect as it is related to the kinds of ions being ab- 

 sorbed. LUNDEGARDH and BURSTROM (1933) have 

 elaborated a theory of anion respiration. This theory 

 postulates that there exists in plant tissues a basic 

 respiration and that this is augmented by a respiration 

 stimulated by the absorption of anions (although sec- 

 ondarily influenced by cations). It is this anion 

 respiration which provides energy for the accumula- 

 tion of the anions. The cation is thought to be ac- 

 cumulated only as a consequence of the accumulation 

 of the anions. The cations are conceived to be liberated 

 at internal phases of the cell after they are first taken 

 up by the protoplasm through a process of adsorption. 

 Many of the studies on potato discs and on roots in 

 this laboratory and in Steward's laboratory are not 

 consistent with the hypothesis of a special anion 

 respiration in the sense of LundegArdh. It would not 



