LEAVES 217 



supply of oxygen for respiration, and of carbon dioxide 

 for carbohydrate synthesis. In stagnant swamps and 

 undrained ponds, however, the oxygen supply is often 

 very scant. In plants living under such conditions 

 there are frequently present in the interior of the plant 

 extensive air chambers for storing air. By means of 

 this "inner atmosphere," respiration and carbohydrate 

 synthesis are much aided Avhen air is not available. 

 In water plants those air spaces make the plant 

 buoyant. In the water hyacinth, for example, the large 

 air spaces in the petioles make the plant so light that 

 it floats. Many sea weeds are buoyed up by so-called 

 air bladders. 



Questions 



1. Name the parts of the outside of a leaf. 



2. What is the structure of the inside of a leaf? 



3. What arc stomates? Where are they found? 

 How numerous are they.? 



4. What is the function of stomates? 



5. What is chlorophyll? 



6. Is chlorophyll of any importance to us? 



7. What are the raw materials used by plants for 

 the manufacture of carbohydrates? 



8. Under what conditions are these raw substances 

 combined to form carbohydrates? 



9. What is the waste product in this process ? 



10. Why is this process of so much importance to 

 animals? 



11. In what parts of plants is food stored? 



