The Fascination of Flowers [ 29 1 



sunlight is one of the "raw materials" needed for making living 

 matter.) 



The "manufacturing" cells are protected on top and bottom 

 surfaces by a skin, or epidermis, which is perforated with innumer- 

 able tiny holes. Each hole is surrounded by two guard-cells the 

 only surface cells that contain chlorophyll. Through the little 

 holes the leaf constantly takes in and gives off oxygen, carbon 

 dioxide, and other gases as well as water vapor. 



How CHLOROPHYLL MAKES FOOD FOR PLANTS 



Before the leaf "factory" can operate, it requires one more 

 item. This is a watery solution, containing many substances, that 

 originates in the soil, enters the plant roots, works its way up the 

 stem and at last into the leaf. 



Within each leaf, carbon dioxide much of it comes from the 

 air we exhale is separated into carbon and oxygen. In the same 

 way, water is broken down into oxygen and hydrogen. The leaf 

 cells combine the carbon with the hydrogen and oxygen into a 

 form of sugar that will nourish the plant. It is the chlorophyll 

 that accomplishes this remarkable feat but it can be done only 

 when sunlight, or artificial light equal to sunlight, is shining on 

 the plant. 



In the daytime plants are our benefactors by releasing oxygen, 

 which purifies the air we breathe. At night, though, they give 

 off carbon dioxide, a gas which is poisonous when it is present 

 in considerable quantity. (This explains why a room with many 

 large house plants should be well aired at night.) 



A scientist has estimated that during the course of a summer 

 a single leaf, suitably exposed to sunlight, manufactures enough 

 sugar to cover itself with a solid layer about one twenty-fifth of 

 an inch thick and this is aside from protein and other food 

 elements! 



Plants Turn Toward the Sun: Your house plants will give you a 

 fine opportunity to observe how leaves are affected by the need 

 for sunlight, in order to continue feeding the plants. Even a small 

 child can observe how the location of the leaves at or near the ends 

 of branches helps expose their surfaces to a maximum of light. 



