How the Plant Grows. 7 



eral salts. These amids are transported to needed points and there 

 changed into the proteins. As a consequence the amids do not 

 usually continue to accumulate in the plant. Just as starch and 

 sugar may be changed one into the other in the plant, so the pro- 

 teins and amids may be changed one into the other as plant neces- 

 sity may require. When germination starts in a seed, an enzyme 

 or ferment contained therein acts upon the insoluble proteins stored 

 in and about the germ and changes them to soluble amids, so that 

 the nitrogen may be transported to the newly forming parts of the 

 plantlet. When corn forage is placed in the silo, much of the pro- 

 teins it then contains is changed back to amids thru the fermenta- 

 tions which occur. 



Very little crude protein is found in the older woody parts of 

 plants, the greater portion always being concentrated at the point 

 of growth, or in the leaves, seeds, and reproductive parts. The 

 germ of seeds is largely protein, and the rich nutritive substances 

 in the grain close about it usually hold much protein. It is in the 

 life-holding protoplasm in the green parts of plants, principally in 

 their leaves, that all the crude inorganic compounds taken up by 

 the plant from air and soil are elaborated into true plant substances 

 by sun power. The life processes of the plant are maintained and 

 all changes are wrought thru its nitrogenous or protein compounds, 

 and a knowledge of such fact is not only of interest, but has many 

 practical bearings for the farmer and stockman. 



6. Mineral compounds. — The elaboration of food materials in the 

 protoplasmic masses, as well as the development of young plants 

 from the seed, requires the presence of mineral matter, or ash, 

 which is found in relatively small amount everywhere thruout the 

 plant. The leaves contain more ash than do the other parts, due to 

 the life processes within the leaf cells and the constant evaporation 

 of water from their surfaces by which the ash in solution is left 

 behind. The ash content of the bark of trees and stems of plants is 

 also often high. 



7. The end of plant effort.— If we study the life history of a 

 plant, we observe that its first effort is toward self-establishment 

 and enlargement. At such time all the elaborated material, as fast 

 as formed, is transferred to the growing parts that the plant may 

 be built up and established. As the plant approaches maturity, its 

 energies are changed from growth to reproduction, or the perpetua- 

 tion of its kind. The nutrients in the juices, which were formerly 

 directed to the growing portions, are now turned toward the re- 



