CONDUCTION OF STIMULI. 



104. Touch stimulus. Note the effect of touching the leaf of Mimosa pudica: 

 successive folding of the leaflets from, the leaf-tip downwards, followed by a downward 

 movement of the petiole and lastly movements of the other leaves. 



105. Gravity stimulus. The root of a seedling was caused to curve geotropically 

 to a right angle by placing it horizontally. The root was then fixed and stained in iodine. 

 It can now be seen under the microscope that the region of curvature is at some distance 

 from the statocysts. 



