PHYSIOLOGICAL PROCESSES IN PLANTS 



93 



1 inch wide) about one inch from the cut end. Observe results 

 for several days. 



2. What happens just above the girdle? What effect on the 

 roots below the girdle ? 



Conclusions. 1. Is the path of soil 

 water, etc., interfered with by gir- 

 dling ? 



2. Can food material pass from 

 the leaves, etc., back to the roots, 

 when the stem is girdled? Keasons? 



3. Is the path of the soil water 

 therefore within the stem proper or 

 in the inner layer of bark ? 



4. Is the path of the formed food 

 (as sugar, etc.) therefore within the 

 stem proper, or the inner layer of 

 bark? 



5. Explain Figure 24, writing a FIG. 24. Diagram to show 



paragraph of description. the re s ions in the stem 



through which the raw food 



materials pass up the stem, 

 and food made in the leaf 

 passes down the stem. (Af- 

 ter Stevens.) 



e: Condition of Food passing 

 through the Stem 



Method. Half fill a tube 

 with starch and water, and 

 another with glucose and 

 water. Put both tubes in a 

 vessel of water as indicated, 

 with the water on a level with 

 the liquids in the tubes. After 



FIG. 25. -Experiment showing the os- a day or so test the ]i qu ids in 

 mosis of sugar, and the non-osmosis ,, -, , , 



of starch, a, tube with starch and the V6SSels f r starch aild f r 

 water ; 6, tube with sugar and water. Sugar. 



