XLL— THE MECHANICAL AND ELECTRICAL RESPONSE 

 OF ROOT TO VARIOUS STIMULI 



By 



Sir J. C. BosE. 



Ix the last chapter we f»tudie«l the electric response of 

 the shoot to the stimulus of gravity, and found that the 

 excitatory effect of that stimulus is similar to that of other 

 forms of stimulation. Before taking up the subject of the 

 geo-electric response of the root to gravitational stimulus, 

 I shall describe the effects of other forms of stimuli on the 

 mechanical and electrical response of the root. 



In connection with this subject, it should be borne in 

 mind that the responsive curvature in the root takes place 

 in the sub-apical growing zone which is separated by a 

 certain distance from the tip. The stimulus is therefore 

 direct when applied at the responding growing region ; it is 

 indirect when applied at the tip of the root. The interven- 

 ing distance between the root-tip and the responsive zone of 

 growth is semi-conducting or non-conducting. 



I shall proceed to give an account of my investigations 

 on the response of the root to direct and indirect unilateral 

 stimulation. Wt; shall study : — 



(1) The Mechanical response to Direct unilateral sti- 



mulus. 



(2) The Electrical response to Direct unilateral stimu- 



lus. 



(3) The Mechanical response to Indirect unilateral 



stimulus. 



