CHAPTER VII. 

 PATH OF MOVEMENT OF LIQUIDS IN PLANTS. 



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

 seen tliat large quantities of water or solutions move upward 

 through the stems of plants. We are now led to inquire 

 through what part of the stems the liquid passes 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 by the following 

 trial. 



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

 of the red dyes. — We may cut off 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 dye known as fuchsin to make a deep 

 red color (other red dyes may be used, but this one is especially 

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

 me-not" (impatiens) will be found a very iiseful plant, or the 

 garden-balsam, which may also be had in the winter from con- 

 servatories. Almost any plant will do, however, but we should 

 also select one like the corn plant (zea mays) if in the summer, 

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

 from the conservatory. If seedHngsof the castor-oil bean are at 

 hand we may cut off some shoots which are 8—10 inches high, 

 and place them in the solution 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 see through the 

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

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



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