CHAPTER V. 



PATH OF MOVEMENT OF WATER IN PLANTS. 



93. In our study of root pressure and transpiration we ha\e 

 seen that large quantities of water or solutions move upward 

 through the stems of plants. ^^'e are now led to inquire 

 through what part of the stems the li(iuid jiasses in this upward 

 movement, or in other words, what is the path of the "sap" as 

 it rises in the stem. This we can readily see l>y the following 

 trial. 



94. Place the cut ends of leafy shoots in a solution of some 

 of the red dyes. — We may cut olT leafy shoots of various plants 

 and insert the cut ends in a vessel of water to which have been 

 added a few crystals of the dve known as fuchsin to make a deep 

 red color (other red d\es may be used, l)ut this one is especially 

 good). If the study is made during the summer, the "touch- 

 me-not" (impatiens) will be found a very useful jilant, or the 

 garden-balsam, which mav also l>e had in the winter from con- 

 servatories. Almost anv plant will do, howe\'er, but we should 

 also select one like the coin plant (zea mavs) if in the sunnner, 

 or the petioles of a plant like caladium, which can be obtained 

 from the conservatory. If seedlings of the laslor-oil bean are at 

 hand we may cut off some shoots which are S-io inches high, 

 and ]dace them in the solutiou also. 



95. These solutions color the tracts in the stem and leaves 

 through which they flow. — .After a few hours in the case of the 

 impatiens, or the more tender plants, we can sec through the 

 stem that certain tracts are colored red by the solution, and 

 after 12 to 24 hours there may be seen a red coloration of the 



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