Plant Study 7 



Water in plants. Water is composed of the elements, hydro- 

 gen and oxygen. It not only forms a part of the body of the 

 plant, but carries dissolved food to all parts root, stem, and 

 leaves and regulates the temperature of the plant during 

 growth. 



Ash in plants. The mineral matter of plants is the ash. 

 It is that portion that remains after the plant has been burned 

 and includes all the materials, except water and nitrogen, that 

 the plant takes from the soil. The elements in the ash of 

 plants are potassium, phosphorus, calcium, magnesium, iron, 

 sulfur, sodium, chlorine, silicon, manganese, and aluminum. 



Carbohydrates in plants. The carbohydrates are composed 

 of carbon, hydrogen, and oxygen. They -include chiefly 

 starches, sugars, cellulose, and pentosans. Starch in its vari- 

 ous forms is more or less familiar to all and is found most 

 largely in the seeds, roots, and tubers. Plant-sugar includes 

 cane-sugar, beet-sugar, maple-sugar, and glucose. Cellulose 

 is the fiber of plants. It is found more largely in the stems and 

 leaves than in the seeds. It is neither soluble nor digestible. 

 Pentosans aid the cellulose in giving form to the plant-tissue ; 

 they are insoluble in pure water, but soluble in dilute acid. 

 When acted upon by the digestive juices in the animal-body, 

 they are dissolved and are useful as nourishment. 



Fat in plants. In nearly all plants fat is present. It is 

 found more largely in the seeds than in the other parts. Flax, 

 rape, and cotton seeds are rich in fat. The percentage in plants 

 varies considerably. In tubers it is sometimes a few hundred ths 

 of one per cent, while in the flaxseed it is thirty-five per cent. 

 Corn is often five per cent fat, wheat two per cent, hay about 

 one and one-half per cent, and straw less than one-half per cent. 



Protein in plants. The term protein is used to designate 

 those organic compounds that contain the four elements, car- 

 bon, hydrogen, oxygen, and nitrogen. Some contain phos- 

 phorus, sulfur, or iron in addition. Protein is a general term 

 and the number of compounds included in this group is very 



