210 SEED AND FRUIT DISPERSAL 



Uses. Seeds and their products are of great economic use. 

 One has only to think of cotton, flaxseed, coffee, beans, peas, 

 lentils, nux vomica, peanuts, mustard, nutmeg and hundreds 

 of garden and flower seeds to realize the economic uses of 

 seeds. 



Dormancy or Rest Period. Seeds when mature lose most of 

 their water, a fact which enables seeds to perform their 

 functions so successfully. Dormancy refers of course to the 

 period which seeds usually remain under favorable conditions, 

 before germinating. During this period respiration is reduced 

 to the minimum and no new tissue is formed. 



Longevity. The life of the seed varies from one to several 

 years. Often this period can be extended by selecting seed 

 only from hardy plants, by keeping only mature seeds, and 

 by proper methods of storing. 



Viability. 1 The viability or the power of seeds to germi- 

 nate is an important factor in the selection of seeds. All 

 seedsmen and many dealers and planters apply the germi- 

 nation test to seed offered for sale or before planting. Most 

 dealers will not offer seed for sale unless 75 per cent is viable. 



Germination. Germination is the development of a seed 

 into a seedling. The time required for this varies. 



Necessary Conditions* For every seed there is a minimum 

 amount of water and heat required and a maximum amount 

 beyond which germination will not take place or which will 

 retard further growth after germination has begun. 



Stages of Germination. There is no sharp line of demar- 

 cation separating the different stages of germination. These 

 overlapping stages may be briefly summarized as follows : 



1. Absorption of water and swelling of the seed. 



2. Enzyme action on the reserve food rendering it soluble. 



3. Absorption of food and oxygen and active respiration. 



