HOW WATER MOVES THROUGH THE PLANT. S3 



'ater on the surfaces of the leaves, or at the cut ends, before it may have 

 ondensed there, we infer that the water escapes from the leaves in the form 

 f water -vapor, and that this water vapor, when it comes in contact with the 



Fig. 45. Fig. 46. 



Leaves removed to show drops of water Photographed after the water has been 



on inside of jar. wiped from inside of jar. 



lrface of the cold glass, condenses and forms the moisture film, and later 

 le drops of water. The leaves of these cut shoots therefore lose water in 

 le form of water vapor, and thus a loss of turgidity results. 



Demonstration 18. 



96. Loss of water from growing plants. — Suppose we now take a small 

 nd actively growing plant in a pot, and cover the pot and the soil with a 

 leet of rubber cloth which fits tightly around the stem of the plant (or the 

 ot and soil may be enclosed in a hermetically sealed vessel) so that 

 le moisture from the soil cannot escape. Then place a bell jar over the 

 lant, and set in a. brightly lighted place, at a temperature suitable for 

 rowth. In the course of a few minutes on a dry day a moisture film forms 

 1 the inner surface of the glass, just as it did in the case of the glass jar 

 mtaining the cut shoots and leaves. Later the moisture has condensed so 

 lat it is in the form of drops. If we have the same leaf surface here as we 

 id with the cut shoots, we will probably find that a larger amount of 

 ater accumulates on the surface of the jar from the plant that is still at- 

 ched to its roots. 



97. Water escapes from the surfaces of living leaves in the 

 irm of water vapor. — This living plant then has lost water, 

 hich also escapes in the form of water vapor. Since here there 



