62 



PLANT BIOLOGY 



stored until needed. Whenever large amounts of starch, 

 sugar, protein, or fat are thus stored, the organs containing 

 these substances frequently become enlarged (e.g. carrot (Fig. 

 81), potato (Figs. 49, 60), and onion) and the walls of the cells 

 in these organs usually remain thin and soft, permitting the 

 inward and outward passage of food. (See Fig. 9.) 



73. Summary of functions of the parts of the nutritive 

 organs of green plants. 



