THE DEPENDENCE Op GROWTH UPOM TRANSPIRATION 

 UNDER DIFPERElvrT CONDITIONS Op HUMIDITY. 



The phenomenon of growth is one of great oomplexity 

 it being the resultant of several processes 'prhioh are 

 carried on within the plant, the several factors concerned 

 with it being in turn influenced to a greater or less de- 

 gree by external conditions. 



The relation of one of these processes, transpiration, 

 to growth has given rise to much discussion among plant 

 physiologists and is still an unsettled question. 



Among those who lootc upon transpiration as primarily 

 a vital process there are three general views held regard- 

 ing its role : (1) To enable the plant to take up a suffic- 

 ient supply of mineral salts ; (2) To prevent high temper- 

 atures in the plant ; (3) That it is a necessary evil, 

 necessary in that moist membranes imiet be exposed for the 

 exchange of gases and at the same time an evil since sucli 

 large quantities of water are required. 



Strasburger, Noll, Schenlc and SOhimper (12) hold that 

 ^the plants would be unable to obtain a sufficient siipply of 

 nutrient salts if they took up only as much water as they 

 could retain and maKe \ise of. 



