SEEDS AND SEEDLINGS 11 



is affected by the conditions under which the seed is devel- 

 oped, the age of the seed and the conditions of storage. 

 Seeds developed under unfavorable conditions will produce 

 inferior plants. Immature seeds lack vitality because of in- 

 sufficient stored food, and seeds past their maturity lose 

 vitality with increasing age. High moisture content and 

 high temperatures in storage increase respiration and lower 

 vitality. 



Longevity refers to the length of time a seed can retain 

 its vitality in storage. The longest record of longevity in 

 seeds is held by Indian lotus, which germinated after being 

 buried in peat for two hundred years. Many seeds remain 

 viable for ten or more years, but most of our garden seeds 

 have a longevity of less than five years. The facts regarding 

 the age and germination after thousands of years of seeds 

 from Egyptian tombs are too fragmentary to be credited 

 here. 



The seed uses the stored food while it develops into a seed- 

 ling by first sending a radicle or primary root into the soil 

 and later the plumule or shoot into the air (Figs. 4 and 5). 

 The seed should be planted deep enough to anchor it while 

 the primary root enters the soil, otherwise, the root will push 

 the seed out of the soil instead of itself going deeper into the 

 soil. If the seed is planted too deep, energy is wasted push- 

 ing the shoot through the soil, so that in extreme cases it 

 may be unable to penetrate. The early root growth is much 

 more rapid than the shoot growth. This enables the root to 

 absorb water and mineral salts for the rapid growth of the 

 entire plant which follows. 



Since the seed must furnish all the food for the early 

 growth of the seedling, it is not surprising to find a well- 

 balanced combination of starches, proteins, minerals, en- 

 zymes and vitamins in storage form. Frequently minerals 

 are in larger amounts at the seed surfaces, but the enzymes 

 and vitamins are more concentrated in the embryo. 



