FERTILIZERS 7 



on hot days give off more. The leaves of fruit trees 

 may be made large or small by an adequate or inad- 

 equate supply of moisture. ',The larger and healthier 

 the leaves, the more plant food]is>laborated^and the 

 better the growth and the crop. So the transpira- 

 tion system and its healthy activities are very 

 directly connected with the production of fruit. 



4. Any serious or prolonged check to the process 

 of transpiration necessitates a long time for full 

 recovery, frequently several years. A severe wilting 

 will show for a year, but a slight wilting usually 

 fully recovers after watering. Thus the importance 

 of a regular and sufficient supply of water is evident. 



Water is the common carrier of all the plant's food, 

 whether the food is derived from the air or from the 

 soil (13), the only positively known exceptions being 

 the absorption of carbon and oxygen by respiration. 



The whole movement of water from the root hairs 

 to the leaf and back to other parts of the plant and 

 fruit, is confined to the cambium layer in which are 

 contained the xylem (upward flow) and phloem 

 (downward flow) tissue. 



LEAVES. 



5. A good leaf is essential to the best results. 

 Leaves put the plant in communication with sun- 

 light, under which influence sap is changed and many 

 products, incident and essential to growth, are 

 manufactured. It is believed that all of the plant 

 food brought into the 'tree by water, undergoes 

 some change in the leaf (digestion) before it is finally 

 added to the various tissue of the plant. If the leaf 

 has been stunted or impaired by drought, frost or 

 fire, it manufactures less of the products essential 



