CONTEXTS XV 



CHAPTER IX 



ACCELERATION OF GROWTH IN SUBTONIC PLANTS 



ON STIMULATION 



PAGE 



Acceleration of growth under light— Modifying effect of tonic condi- 

 tion on response to stimulation — Continuity between abnormal 

 and normal response — Enhanced rate of growth under subminimal 

 stimulation — Revival of arrested growth under photic stimula- 

 tion — Acceleration of growth in subtonic organ under electric 

 stimulation ...••••••• °° 



CHAPTER X 



EFFECT OF MECHANICAL STIMULATION ON GROWTH 



■ Effect of feeble and of moderate stimulation — Effect of wound — 

 Twining of tendrils — Tactile pits in certain tendrils — Effect of 

 indirect stimulation on growth of tendril — -Effect of direct electric 

 ^ stimulation — Immediate and after-effect of mechanical stimulation 



on growth of tendril — Positive tropic curvature under unilateral 

 mechanical stimulation — Negative tropic curvature under 

 indirect unilateral mechanical stimulation — Electric response of 

 proximal and distal sides of the tendril— Contractile response of 

 the less excitable side of tendril — Inhibitory action of stimulus . 87 



CHAPTER XI 



THE PHOTOTROPIC EFFECT OF LIGHT 



The hvpothesis of specific positive and negative irritability of 

 different organs— The Phototropic Recorder— Positive photo- 

 tropic response of pulvinated organs — Positive curvature of 

 growing organs — Determination of the latent period — Induced 

 variation of growth bv Hght from a single spark — :\Iaximum 

 positive curvature under continued Hght — Relation between 

 quantity of light and induced curvature — Effect of increasing 

 intensity of hght — Effect of increasing duration of exposure — 

 Effect of the angle of the incident light loi 



CHAPTER XII 



THE MECHANISM OF PHOTOTROPIC CURVATURE 



The effects fof direct and indirect stimulation — Enhancement of 

 turgor in leaf of Mimosa under indirect stimulation — Dual impulses 

 generated on stimulation, a quick positive and a slow negative 

 — Longitudinal transmission of impulse — Effect of transverse 

 transmission of impulse across the stem under photic stimula- 

 tion — Transverse transmission of impulse und-er electric and 



h 



