444 INDEX 



Photic stimulator, 159, i6o 



Photo-Geotropic Balance, 309 ; effect of coal-gas on, 310 



Photometric Recorder, see Radiograph 



Photonastic phenomena under light applied above and below, 157, 429; 

 of leaflet of Averrhoa, 157, 168; of leaflet of Mimosa, 157, 158, 169; 

 continuity between, and phototropic reactions, 170, 428 



Phototropic curvature, mechanism of, 116 ; effect of direct and indirect 

 stimulation, 117 ; effect of longitudinally transmitted impulse, 119 ; 

 effect of transversely transmitted impulse under photic, electric, and 

 radio-thermal stimulation, 121, 122, 123 



Phototropic curve : characteristics of, 150, 428 ; definition of susceptibility, 

 149 ; variation of susceptibility at different parts of, 151 ; complete 

 curve of pulvinated organ, 154 ; complete curve of growing organ, 155 



Phototropic Recorder : for shoot, 103 ; for root, 140 



Phototropism of shoot : positive response, 104, 105 ; the latent period, 

 106 ; effect of increasing intensity of light, 109 ; effect of increasing 

 duration of exposure, m ; effect of angle of inclination of light, 112 ; 

 relation between quantity of light and tropic response, 114 ; partial 

 or complete neutralisation under long exposure, 133, 134; fatigue- 

 relaxation as contributory factor in transformation of positive to 

 negative curvature, 135, 136 ; positive, dia-, and negative, 137 



Phototropism of root : reaction to unilateral stimulation of root-tip, 141 ; 

 effect of simultaneous unilateral stimulation of root-tip and growing 

 region, 143 ; positive reaction of Sinapis transformed into negative 

 under continuous unilateral stimulation, 145. See also Radio-thermo- 

 tropism of shoot and of root 



Porana paniculata, autonomous torsion of : effect of variation of tempera- 

 ture on, 388, 3S9 ; of indirect stimulation on, 399, 403 ; of diffuse 

 sunlight on, 401 ; of geotropic stimulation on, 404 ; combined effect of 

 unilateral geotropic and photic stimulation on, 418 



' Praying ' Palm, the diurnal movement of, 224, 228, 229 ; physiological 

 cause of, 225 ; active not passive, 229 ; relative effect of light on, 

 229 ; of variation of temperature on, 230. See also Thermo-geotropism 



Pulsation, of growth, 18 ; of Mimosa leaf, 270 



Pulvinated organ, contractile response of, 68 ; relation between quantity 

 of incident light and phototropic curvature, 114 ; complete photo- 

 tropic curve of, 153 ; principal types of response in, 171 ; response 

 to direct radio-thermal stimulation, 179 ; differential geotropic 

 excitation of, 290, 291, 303 ; effect of carbon dioxide on geotropic 

 response of, 303 



Pulvinated organ, torsional response to lateral stimulation: by light, 253, 

 411 ; by thermal radiation, 255 ; by geotropic stimulation, 307 



Pulvinus and growing organ, similarity of response of, 55, 56, 68 



QuADRUPLEX Recorder, Oscillating, 209 ; Geotropic, 282 



Radial organs, response in, 171 

 Radiograph, Self -Recording, 1 97,^206 

 Radio-Thermal Stimulator, 175 

 Radio-thermotropism, 1 74 



