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GREEN PLANTS AS FOOD MAKERS 



means of which soil water, with the dissolved mineral materials, 

 are taken into the root. But again we are met with a problem. 

 Food is manufactured in the leaves of the plant, but all parts of 

 the plant need that food. It is common knowledge that food is 

 stored in seeds, in fruit, in stems such as the asparagus and in the 

 roots such as turnips, radishes, and carrots. How then does the 

 food get from the leaves to the various parts of the plant, and how 

 does the water get from the roots to the leaves themselves where 



Wright Pierce 



In the growth of the bean plant, notice the gradual decrease in size and final disappear- 

 ance of the cotyledons. How does the plant obtain food for growth after the cotyledons 

 have been used? 



it is used in the manufacture of foods ? Here again we must call 

 the microscope into play. You are all familiar with the fact 

 that a celery stem is made up of a watery material with long, 

 threadlike fibers in it. If we were to examine one of these thread- 

 like structures under the microscope, we should find that it was 

 made up of a large number of little tubes of various diameters, 

 some large and some small. The larger tubes carry water, some 

 of the smaller ones, food substances. We shall later find that these 

 bundles of tubes, called fihrovascular bundles, are arranged in a 



