Addresses — Plant Development and Training. 219 



tact with the air, they remain sound indefinitely. In order to the 

 successful germination of seeds, they must be abundantly supplied 

 with moisture, heat, and air. Light is necessary to the develop- 

 ment of the plant, but it retards if it does not altogether prevent 

 germination. During the process of germination, seeds absorb 

 oxygen, and give off carbonic acid — that is, a portion of the carbon 

 of the seed is oxidized, and the process of oxidation produces heat. 

 Light produces a contrary effect; it deoxidizes the carbonic acid, or 

 resolves it into its primary elements — carbon and oxygen. 



The amount of heat required to germinate seeds, varies with the 

 kind. Wheat, rye, and most of the grasses germinate at a lower 

 temperature than oats, barley, flax and Indian corn. Many of the 

 exotic vegetables cultivated in our gardens, require much heat and 

 moisture to induce germination, and hence, it is usual to start them 

 in hot-beds. They gradually, however, become more hardy, and 

 germinate more kindly after becoming partially acclimated. So 

 plants taken from a cold climate to a warm one, change their con- 

 stitution somewhat, and after many years if taken back to a colder 

 climate, they will be found to have lost some of their hardiness. 



In the process of germination, seeds also actually give off heat, 

 so much so sometimes, if placed in masses, as in malting, to sensibly 

 affect the air. The heating of grain when wet, and laid in piles, is 

 a phenomenon familiar to many. The moisture and heat being 

 right, the grain sprouts, heat is germinated, and the transformation 

 of starch or gum to sugar is effected, by its combination with acid, 

 for during germination, acetic acid and a peculiar substance — 

 diastase — is formed, which has the power of converting starch into 

 sugar. Sugar is carbon, and carbon is necessary to the plant. 

 This had been previously stored up in the seed to support it until 

 it could push forth its plumule and radical — the first rising above 

 ground, and the latter pushing its way below. The first to form 

 leaves, and the latter to draw nourishment held in solution by the 

 moisture of the earth. 



The embryo plant is contained in the seed, and may be easily 

 seen by dissection under the microscope. The primary leaves of 

 many seeds, as the legumes, peas, beans, etc., are formed of the 

 two lobes of the seed itself. These rise immediately above ground. 

 In other cases — as in wheat — the seed remains below ground, and 

 is gradually absorbed, ust as the seed-leaves of beans are partially 



