68 



MINERAL SALTS ABSORPTION IN PLANTS 



Cell 

 expansion i 



Meristematic cells 

 micro-organisms 



ACTIVELY 

 DIVIDIMG CELLS 



Absorption into 

 cytoplasm and 

 organelles 



Onset of cell 

 division 



Excised roots 

 grown in low 

 solt solutions 



Excised roots 

 grown in high 

 solt conditions. 

 Young attoched 

 leaves 



RAPIDLY METABOLIZING 

 AND EXPANDING CELLS 

 WITH LOW SALT CONTENT 



Slowly growing 

 coenocytes. 

 Mature 

 ottoched leaves 



Ropid obsorption 

 in vacuoles 



RAPIDLY METABOLIZING 



AND EXPANDING CELLS 



WITH HIGH SALT 



CONTENT 



Accumulation dependent 

 on growth by cell 

 enlorgement 



MATURING CELLS WITH 

 HIGH SALT CONTENT 

 LOW METABOLISM 

 AND SLOW GROWTH 



MATURE CELLS RESTORED 

 TO ACTIVE METABOLISM 



Renewed obllity 

 fo accumulate 



DORMANT CELLS WHICH 

 HAVE CEASED GROWTH 

 AND HAVE LOW 

 METABOLISM 



Accumulotion 

 suspended 



MATURE CELLS 



INCAPABLE OF 



FURTHER GROWTH 



Slices of 

 storoge 



tissues woshed 

 in aerated 

 solutions 



Storoge 



tissues copable 

 of rejuvenation 



Porenchyma of 

 mature fruits 

 and bulb scales. 

 Cotyledons 



Fig. 23. Salt accumulation in relation to growth and metabolism (modified 

 from Steward and Sutcliffe, 1959). 



a state of senescence or of dormancy. Senescent cells gradually 

 degenerate and release salt to their surroundings, but dormant cells 

 on the other hand can be stimulated to metabolize actively, syn- 

 thesize protein and absorb salt again under suitable conditions. 

 Some of the relationships between growth at the cell level and salt 

 absorption are summarized diagrammatically in Fig. 23. 



There is also a close correlation between growth and the 

 absorption of salt in whole plants. The phase of rapid vegetative 

 growth is accompanied by a marked increase in the amount of 



