SEEDS CAN NOT GERMINATE WITHOUT AIR 6l 



dish germinate? They were in contact with water in 

 both dishes, and both dishes were kept in a warm 

 room. In the right-hand dish, however, the kernels 

 were in contact with plenty of air, while in the other 

 dish most of the air was shut out. We all know that 

 seeds will not germinate so long as they are dry, and that, 

 even though they have plenty of water, they will not ger- 

 minate in a very cold place. But this experiment shows 

 that, although wheat seeds may have plenty of -water and 

 warmth, they will not germinate unless they also have 

 plenty of air. The same is true of most of the seeds com- 

 monly planted on the farm or in the garden. 



Some Seeds Contain Air. The seeds of some plants 

 that grow in water, as the water lily and rice, and of a few 

 land plants, as Indian corn, may germinate under water. 

 Dry seeds usually contain pores that are filled with air, 

 and water also usually contains some air. These seeds 

 are able to get enough air from their pores and from the 

 water, to enable them to germinate. If they are soaked 

 for a time in cold water to expel the air within them, 

 and are then sealed up in a fruit jar of water from which 

 the air has been expelled by long boiling, they can not 

 germinate. No seeds can germinate without access to air. 



Packed Soil Does Not Admit Air. In the experiment 

 shown in Figure 29, a few radish seeds were planted in 

 soil that was wet enough to be easily worked up in the 

 hands, like soft putty. The soil was then packed down 

 closely around the seeds in one of the dishes, and left 

 loose in the other. We now see that the radish seeds have 

 germinated in the loose soil, while they have germinated 

 very poorly, if at all, in the packed soil. They failed to 



