CHAPTER X. 



HOW PLANTS OBTAIN THEIR FOOD, II. 

 Seedlings. 



202. It is evident from some of the studies which we have made in con- 

 nection with germination of seeds and nutrition of the plant that there is a 

 period in the life of the seed plants in which they are able to grow if sup- 

 plied with moisture, but may entirely lack any supply of food substance 

 from the outside, though we understand that growth finally comes to a 

 standstill unless they are supplied with food from the outside. In con- 

 nection with the study of the nutrition of the plant, therefore, it will be well 

 to study some of the representative seeds and seedlings to learn more accu- 

 rately the method of germination and nutrition in seedlings during the ger- 

 minating period. 



203. To prepare seeds for germination. Soak a handful of seeds (or 

 more if the class is large) in water for 12 to 24 hours. Take shallow crockery 

 plates, or ordinary plates, or a germinator with a fluted bottom. Place in 

 the bottom some sheets of paper, and if sphagnum moss is at hand scatter 

 some over the paper. If the moss is not at hand, throw the upper layer of 

 paper into numerous folds. Thoroughly wet the paper and moss, but do 

 not have an excess of water. Scatter the seeds among the moss or the folds 

 of the paper. Cover with some more wet paper and keep in a room where 

 the temperature is about 20 C. to 25 C. The germinator should be looked 

 after to see that the paper does not become dry. It may be necessary to 

 cover it with another vessel to prevent the too rapid evaporation of the water. 

 The germinator should be started about a week before the seedlings are 

 wanted for study. Some of the soaked seeds should be planted in soil in 

 pots and kept at the same temperature, for comparison with those grown in 

 the germinator. , 



204. Structure of the grain of corn. Take grains of corn that have been 



97 



