344 



CHAP. XXX. THE GEO-PERCEPTIVE LAYER 



found to exhibit electric response of moderate intensity 

 under the stimulus of gravity. It is sensitive whilst the 

 flower-buds are still closed, but insensitive after the opening 

 of the flower. The maximally excited layer was at a depth 

 of 0-3 mm., which also contained the starch-grains. 



Tiger Lily. — The flower-bud of this plant is strongly 

 geotropic. It gave the maximum geo-electric response at 

 a depth of 0-3 mm. The starch-grains occurred very near 

 this layer. 



Convolvulus. — This gave the maximum geo-electric 

 response at a depth of 0-3 mm. from the surface, and the 

 starch-layer was found at 0-28 mm. below the surface. 



The table given below embodies the results obtained 

 with different plants. Though the maximal excitation 

 occurs at unequal depths in different species of plants, the 

 maximally excited layer is found to coincide wdth the 

 starch-sheath. 



Table XXV. — Geo-Electric Response at Various Depths in 



Different Plants. 



Duplication of Geo-Perceptive Layer 



The experiments described above brought out the definite 

 fact that during the passage of the probe from the surface 

 to the centre, it encounters a particular starch-layer, at 

 which the geo-electric response is at its maximum. From 



