PLANT GROWTH 59 



tioned. In germination box tests in the green house, at a temperature 

 of 80 degrees F., corn has sprouted distinctly in four days. 



Early planted corn on ground which has been well prepared, in 

 order to admit the surface air, will appear in 10 to 12 days or sooner. 

 Listed corn on low ground sometimes requires two weeks or more 

 before it can be seen in the furrow. 



THE GROWTH OF PLANTS 



The growth, of plants is a natural process. It is a cellular develop- 

 ment which usually results in increase of volume and weight. This 

 activity is the expression of life. During the early period of existence 

 of a plant, this development takes place in all the parts at the same 

 time. Later, centers of growth are formed, usually near the tips of 

 roots, stalks and branches. In cereals and grasses, growth takes 

 place at the base of each internode and also at the tip of the stem. 



THE ESSENTIALS FOR THE GROWTH OF GREEN 

 PLANTS ARE: 



1 . Constitution. 



2. Water. 



A. The absorption of water 



B. Its uses. 



(i) An essential constituent of the plant. 



(2) Regulates temperature of plant. 



(3) Maintains turgidity. 



(4) Aids in the physical changes in plant food. 



(5) Enters into the chemical processes within the 



plant. 



(6) Transports plant food. 



3. Proper temperature. 



4. Light. 



5. Plant Food. 



A. From the air. 



(i) Oxygen. 



(2) Nitrogen. 



(3) Carbon. 



B. From the soil. 



(1) Nitrogen. 



(2) Phosphorus. 



(3) Potassium 



(4) Calcium. 



(5) Others. 



