278 LIFE MOVEMENTS IN PLANTS 



Indirect stimulus induces in growing organs an enhance- 

 ment of rate of growth. 



Unilateral application of stimulus causes an expansion 

 higher up on the same side to which the stimulus is 

 applied ; the result is an induced convexity, a movement 

 away from the stimulus, i.e., a negative curvature. Direct 

 stimulus applied unilaterally at the responding region 

 induces, on the other hand, a positive curvature. 



