Lecture 6 



— 145 — Biochemical Problems 



protein synthesis are immediately concerned with salt 

 absorption, although, as Steward has pointed out, the 

 salt accumulating capacity of the roots is the result 

 of active growth and protein synthesis in a preceding 

 growth period, during which the roots could not 

 satisfy their capacity to accumulate salt for the reason 

 that the supply of the latter was deficient. Further- 

 more, in accordance with recent views based on isotope 

 studies it seems conceivable that in the actively metab- 

 olizing roots transformations of proteins proceed 

 rapidly even when no net changes in nitrogen com- 

 ponents are demonstrable. 



EmCT OP SILTS AND AEIATION OK TOK NlTROaEH rRACTlONS OP POTATO DISCS. Au. qUAHTTTIBa OP ITTTBaonf IM Ma PI* «Uli OT 



INrruL FECfiB TISSUE 



Table 5. — Effects of potassium salt accumulation and aera- 

 tion on nitrogen metabolism of potato discs. (From Steward 

 and Preston, 1940). 



In the researches of Thimann and his co-workers 

 on coleoptiles, an inter-relationship was discovered 

 among growth, protoplasmic streaming, sugar, auxin 

 and catalytic organic acids. Some of these are the 

 same factors concerned with the metabolic processes 

 leading to salt accumulation by roots but we do not 

 know how far we are justified in translating these 

 results to the activities of roots in absorbing salt, espe- 

 cially since the effects of auxin on the growth of roots 

 and on the coleoptile are not alike. 



Progress in understanding the metabolism of plant 

 cells in its relation to salt accumulation is limited by 



