OFFICE OF LEAVES 



use carbon dioxide from the air because of its presence. Lower 

 forms of plants, such as mushrooms and other saprophytes, as 

 well as parasitic plants, do not contain chlorophyll. They must 

 get their food already prepared for assimilation. 



Starch Forming. Plants containing no chlorophyll are unable 

 to break up carbon dioxide to form starch for their own nourish- 

 ment. Fungi which attack growing plants have no chlorophyll in 

 their tissues. They use the starch made by the host plant. The 

 formation of starch is performed only by plants which contain 

 chlorophyll. The starch is manufactured in the presence of sun- 

 light from carbon dioxide and water taken into the tissues. 



6CO 2 +5H 2 O =C 6 H 10 O 5 +12O 



6 Carbon dioxide +5 Water=Starch + 12 Oxygen. 



Office of Leaves. When 

 the young plant began its 

 growth a store of nourish- 

 ment in the seed supplied 

 the energy necessary to 

 cause the plant to burst the 

 seed coats and perhaps to 

 sprout above the soil. The 

 leaves formed near the sur- 

 face of the ground must then 

 supply nourishment to the 

 young plant. From this 

 time on the growing plant 

 receives a large proportion 

 of its nourishment from the 

 air through the leaves. There 

 are breathing pores in the 

 surface of the leaves through 

 which air may come in con- 

 tact with the soft cells within . 



In the making of starch, 

 carbon dioxide is taken in 

 through the pores (or sto- 

 mates) of the leaves where 



it COmeS in Contact With FIG. 3. A self-balanced aquarium. When 



. , iii placed in a window the plants in the aquarium 



Water taken Up by the yOUng give off oxygen, which the animals use. The ani- 



j TT *u *U^ mals produce the necessary carbon dioxide for 



plant. Here, through the the plants, which live principally on it. 



