76 SOILS AND PLANT LIFE 



the supply of food in a grain of wheat may all be used in 

 ten days, producing a vigorous young plant, which is then 

 able to gather and manufacture its own food. In cold, wet 

 weather, it may take the young plant a month to get 

 established. 



It may be stated as a rule that "the shorter the time 

 between planting and germination, the more vigorous the 

 seedling " ; and also that the shorter the time between 

 germination and the stage when the plant is able to main- 

 tain an independent growth, the more vigorous the plant. 



In the early stages of the development of a plant, the 

 root system develops faster than the leaves. This insures 

 the plant a supply of water and anchors it firmly in the 

 ground. 



Our next lesson is to be about plant roots. 



QUESTIONS 



1. What is a seed? 



2. Draw from memory an outline of a grain of com and 

 name its parts. 



3. What is meant by seed germination ? 



4. What are the conditions necessary for the germination 

 of a seed? 



5. How can you prove that a germinating seed needs oxygen ? 



6. Name three ways by which a farmer may assist oxygen to 

 reach the planted seed. 



7. How is heat generated in a germinating seed ? 



8. How can you prove that a germinating seed gives off 

 carbon dioxide? 



9. What is the use of the reserve food stored in a seed? 

 What influence has the amount of reserve food upon the vigor 

 of the seedling? 



10. As a seedling develops into a young plant, in what direc- 

 tion do the plumule and the radicle grow ? Can you tell why ? 



