34 



EXPERIMENTAL PLANT PHYSIOLOGY. 



EXPERIMENT 40. 



DOWNWARD PATH OF SAP. 



In the same manner as above girdle a Willow branch i to 3 

 cm. in diameter by removing a ring of bark near the lower end. 

 FIG. 31. 



Place upright with the lower end sub- 

 merged in water. The buds develop in a 

 normal manner while roots are formed on the 

 lower end, but only above the girdling ring. 

 Since the phloem is removed, the food-mate- 

 rial necessary for the formation of the roots 

 cannot pass the ring. (Fig. 31.) 



EXPERIMENT 41. 



DEMONSTRATION OF PATH OF SAP BY COLORED 

 FLUID. 



Girdled shoot of Sambu- 

 cus. (After Oels.) 



Cut off a semi-transparent stem of Impa- 

 tiens (Touch-me-not), and place the lower end 

 in a water solution of some aniline color. In an hour note that the 

 colored fluid has ascended in the woody fibres in the soft stem. 

 Repeat, using a stalk of a young Corn plant. Allow it to stand in 

 the solution 24 hours, then dissect and determine the path of the 

 fluid. 



