CHAPTER XI 

 STORAGE OF FOOD AND WATER 



Need of Food Storage. — As told in the preceding chapter, 

 plants need food for growth and repair of tissues and to fur- 

 nish energy to keep the life processes going. If food were 

 being made continuously by the photosynthetic tissues day and 

 night, and every day so long as the plant lives, and if the demand 

 for food were uniform all of the time throughout the whole plant 

 there would be no need of storing food for future use. But 

 the actual conditions are quite the reverse of this. 



The photosynthetic tissues do not work at night nor through 

 the winter and dry seasons after the leaves have fallen. And 

 even when the leaves are on the demand for food is by no means 

 the same at all times. More food is needed during the first 

 part of the growing season when growth is most rapid, and 

 more is needed when fruits are forming and advancing to maturity 

 than at other times; and it is of great advantage to plants that 

 they have the power and habit of storing food when the demand 

 for it is relatively slight, for use when the need of it is greater. 



Trees and shrubs, denuded and entering upon their winter 

 rest, are packed with reserve food in roots, trunk, and branches 

 (Fig. 96).. The greater part of this is kept till spring* to sus- 

 tain resumption of growth and the production of fruit, but 

 some of it is necessary to sustain life during the winter. Every 

 organism, so long as it lives, whether active or dormant, requires 

 a certain amount of food to keep its life going. This is true 

 even of dry seeds, although the amount consumed by them is so 

 slight as to be difficult of detection; and parts intended for re- 

 production that become severed from the parent plant must 

 first be stored with food for their nutrition until they become 

 independently established and begin to make food for themselves. 



175 



