72 



Fundamentals of Auxin Action 



LJ 



I- 



or 



O 



> 



< 



10 20 



AGE OF PLANT 



30 



40 DAYS 



Fig. 33. The amount of auxin diffusible from the apices of tomato plants as related 

 to the age of the plant (Kramer and Went, 1949). 



UJ 



q: 



< 

 > 



q: 



3 

 O 



UJ 



> 



< 



125 HRS. 



TIME IN DARK 



Fig. 34. The disappearance of auxin from tobacco plants held in darkness for various 

 intervals of time. Auxin obtained by. diffusion (Avery et al, 1937). 



