The Sugar-Beet Plant 



27 



system, reach to all parts of the soil and come in close 

 contact with the uuiiviciual soil particles. (Fig. 5.) 



By a process kno\Mi as osmosis, water passes from the 

 soil tlirough the cell-wall of the root-hairs into the root, 

 and finally from cell to cell throughout the plant wherever 

 it is needed, or it may pass directly to the leaves where it 

 is lost by tran- 

 spiration. Each 

 day during 

 rapid gro\\-th, 

 the plant in 

 this way takes 

 up and loses 

 several times 

 as much water 

 as its weight. 

 Water is used 

 as a carrier of 

 all foods within 

 the plant. It 



Fig. 



5. — Root-hair extending through the soil in 

 close contact with the soil particles. 



also helps in regulating the plant as 

 well as entering into many of the compounds of which 

 it is made up. More than half of the weight of sugar 

 comes from water which is combined chemically with 

 carbon. 



The mineral compounds which the plant obtains from 

 the soil are : the salts of calcium, magnesium, potassium, 

 iron, phosphorus, sulfur, and nitrogen. These, together 

 with hydrogen and oxygen from water and carbon from 

 the air, make up the ten elements essential to the life of 

 all ordinary plants. If any of these are entirely absent, 

 the plant cannot grow. Many other elements are also 



