

CHAPTER VII 



POSSIBLE RELATIONS BETWEEN SOLUTE 

 DISTRIBUTION AND BEHAVIOR 



The probable importance of solute distribution in influ- 

 encing or determining behavior in ordinary growth as well 

 as in regeneration and related phenomena was mentioned 

 in the introductory chapter. It is not my intention to 

 discuss this topic at any great length, but it does seem worth 

 while to point out the possible bearing of solute movements 

 and factors influencing these movements upon these 

 problems. 



40. Relations between Solute Distribution and Amount 

 of Growth. — It has been repeatedly observed since early 

 times that if stems are ringed, the behavior of parts above 

 and below the ring becomes appreciably different from the 

 normal behavior. Of course, exceptions have been found 

 in those plants with internal phloem or in monocotyledon- 

 ous plants in which ringing does not result in cutting all 

 of the phloem. Experiments and common horticultural 

 practices demonstrating the influence of a change in dis- 

 tribution of solutes following ringing are so extensive and 

 well known that it is not necessary to cite specific data or 

 to discuss these effects in any detail. 



One of the most striking effects of ringing is that the 

 diameter growth, especially that immediately above the 

 ring, is greatly increased, whereas secondary thickening 

 below the ring ceases or is much reduced. This enhanced 

 diameter growth above the ring seems obviously due to 

 an increased supply of carbohydrates, or possibly other 

 foods produced in the leaves, whose downward transport 

 has been stopped by the ring. The reduced supply of 

 carbohydrates, and possibly some special food, to the 

 region below the ring also obviously accounts for the 



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