CHAPTER II 



THE STORAGE OF FOOD IN THE SEED 



6. Importance of stored food for growth of the seedling. A 



very large part of the food of man and of many of the higher 



animals consists of seeds of various 

 kinds, particularly of the grains. Every 

 kind of seed contains some stored food 

 material, though the amount in the 

 poppy seed is but an insignificant frac- 

 tion of that in a 

 FIG. 4, Seeds with endo- 

 sperm, longitudinal sections norse- Chestnut. 



A, asparagus (magnified) ; B, Very often, as 



poppy (magnified). After has already been 



Decaisue -, -, ,, -, 



learned, the rood 



is stored directly in the embryo, espe- 

 cially in the cotyledons. Frequently, how- 

 ever, most of it is deposited in the en- 

 dosperm, which surrounds or lies along- 

 side of the cotyledons (Figs. 2, 3, 4). In 

 either case the slow germination and sub- 

 sequent growth of seeds from which part 

 or all of the food material has been 

 removed shows that its presence is most 

 important in forcing along the growth 

 of the seedling (Fig. 5). 



7. Usefulness of rapid growth of seed- 

 lings. The very existence of the young 



plant may depend upon its being able to FIG. 5. Germinating 



i i TP peas, growing in water, 



make a rapid start in life. Most areas 



of fertile land contain far more seeds 



8 



one deprived of its 

 cotyledons 



