556 



LIFE MOVEMENTS IK PLANTS 



after 6 a.m. and the movement of the tree became reversed 

 from ascent to descent. 



Fig. 199. — Diurnal record of the Sijberia Palm. Upper curve give.s variation 

 of temperature, and the lower curve the movement of the tree. 



I have already shown ; (1) that the diurnal movement 

 just described is due to physiological reaction, and that ihe 

 movement is abolished at the death of the plant; (2) that 

 light has little or no effect, since the thick bark and bases 

 of leaves screen the living tissue from the action of light ; 

 (3) that transpiration has practically no effect on the 

 periodic movement, since such movement takes place in 

 other plants completely immersed under water ; thus 

 Jpomcea aquatica, a water plant, kept under water 

 gave the normal diurnal curve similar to that of the 

 palm. The modifying effect of transpiration was in this 

 case, completely excluded. I obtained similar effect with 

 geotropically carved stem of Basella cordifolia (p. 25) ; 



