52 



CHAP. VI. RELATION OF TURGOR AND TENSION 



of the latent period was due to the fact that on the second 

 occasion there was less loss of time in getting the cells 

 sufficiently turgid for the renewal of growth. The response 

 of growth thus followed for a time after each doling out of 

 water. 



Experiment 27. — A similar result was obtained with a 

 seedling of Vicia Faha, the growth of which, on account of 



drought, was in a state 

 of standstill. Applica- 

 tion of a small quantity 

 of water produced a 

 short-lived revival of 

 growth, which occurred 

 in a pulsatory manner 

 (fig. 23). A second 

 application produced a 

 similar revival, the 

 amplitude and fre- 

 quency of pulsation 

 being quicker than in 

 the last case. Applica- 



FiG. 23. Growth at standstill revived . . 



after irrigation with water. tionof a larger quantity 



A small quantity of water revived growth of W^ater produced a 

 for a short time. Note pulsation of • , , • i r 



growth. (Vicia Faba.) persistent revival of 



growth, the constituent 

 pulsations of which followed each other with such rapidity 

 that it appeared to be continuous. 



Effect on Growth of Variation 

 OF Ascent of Sap 



I have shown elsewhere that the rate of ascent of sap 

 is increased when warm water is used for irrigation, and 

 decreased when cold water is used for the same purpose. 

 Since activity of growth is normally dependent on the 

 ascent of sap, the rate of growth may be expected to be 

 appropriately modified by irrigation with either warm or 

 cold water. 



