PLANT RESPONSE 



53 



(A) The first stimulus was given by a fall of the 

 lever through A, the second through 2 /i, and so on. 

 The response-curves clearly show increasing effect 

 with increased stimulus (fig. 31). 



5 7J 10 12J 



FIG. 32. INCREASED KESPONSE WITH INCREASING VIBRATIONAL STIMULI 



(CAULIFLOWER-STALK) 

 Stimuli applied at intervals of three minutes. Vertical line^'l volt. 



(B) 1. The vibrational stimulus was increased from 

 2-5 to 5 to 7*5 to 10 to 12'5 in amplitude. It will 

 be observed how the intensity of response tends to 

 approach a limit (fig. 32). 



TABLE SHOWING THE INCREASED E.M. VARIATION 



PRODUCED BY INCREASING STIMULUS 



Angle of Vibration 



E.M.F. 



