Gardening 



-*? <---''$ -Upper epidermis 



. 

 duchng tissue i 



Bundle sheath^ 



Bundle sheath^ Guard cell 



Lower 

 epidermis 



FIG. 34. Section of a leaf, very highly magnified. 



goes on in all green parts of the plant, but takes place 

 especially in the leaves. 



Leaves as sugar-making organs. As the term photo- 

 synthesis indicates, the energy used in building up sugar 

 is furnished by the light. Without light, plants cannot 

 do this work ; and when we examine a plant, we note at 

 once that the broad, thin blades of the leaves and the 

 way they are arranged on the plant enables them to 

 catch large amounts of light. This makes it possible 

 for the manufacture of sugar to be carried on rapidly by 

 the plant. 



But it is only when we examine the internal structure 

 of a leaf that we understand how well fitted it is for 



