5. HOW PLANTS GROW. 



Illustrative material: Specimens from parts of living plants 

 illustrating the root, stem, buds, leaves, flowers, and fruit or 

 seed. 



Root Downward, Stem Upward. Figure 1 2 shows 

 a young plant of Indian corn. It grew from the kernel 

 to which it is attached. Two tiny shoots 

 grew from the kernel. One of these grew 

 down into the dark, damp soil to become the 

 root; the other grew up into the light to be- 

 come the stem. Every seed when it ger- 

 minates, that is, when it begins to grow, 

 sends out two shoots, one of which tends down- 

 ward, and the other, upward. During the life 

 of the plant, the stem and root that start in 

 the seed normally continue to grow by the di- 

 vision and growth of certain groups of cells 

 near their tips. 



Root Hairs Figure 13 shows some very pilmiet'^f 



, . . . . . , Indian corn. 



young radish plants that were grown in a seed 

 tester. Notice that each tiny white root that grew from 

 the seed is clothed with a downy fringe that looks like 

 the finest silk. These delicate fibers are called root 

 hairs, and they take up water for the plant. The young 

 roots of most plants are clothed with root hairs. These 

 draw in water from the soil with a certain amount of 

 force. This force, aided by some other forces, causes the 



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