OXIDATION INVOLVED IN GERMINATION 



r-P 



-- S 



FIG. 3. Lengthwise section 

 of grain of corn 



Every observing person who has grown plants from the seed 

 has learned that heat and moisture are necessary to insure ger- 

 mination, but the student will readily discover, too, that air is 

 necessary for anything more than the 

 beginning of germination. 



5. Oxidation involved in germina- 

 tion. Germinating seeds, like all liv- 

 ing things, consume much oxygen, 

 the gas everywhere present in the 

 atmosphere which supports the com- 

 bustion of coal and other fires and of 

 lamps and gas flames. In place of the 

 oxygen which they absorb, sprouting 

 seeds return to the air carbon dioxide, 

 the gas which is produced bv burn- 



L . . y, yellow, proteid part of endo- 



lllg Charcoal, and Which IS One Ot the sperm ;tc, white, starchy part 



products Of burning most kinds of fuel of endosperm; p, plumule; 

 r . . . s, the shield (cotyledon), in 



and of the respiration of animals. 



A thermometer with its bulb im- 

 mersed in a jar of sprouting peas 

 will mark a temperature somewhat 

 higher than that of the room in which they stand. The eleva- 

 tion of temperature is at least partly due to the union of 

 oxygen with combustible materials in the peas. Such a combi- 

 nation is known as oxidation. This kind of chemical change 

 is universal in plants and animals while they are in an active 

 condition, and the energy which they manifest in their growth 

 and movements is as directly the result of the oxidation going 

 on inside them as the energy of a steam engine is the result 

 of the burning of coal or other fuel under its boiler. In the 

 sprouting seed, much of the energy produced by the action of 

 oxygen upon oxidizable portions of its contents is expended in 

 producing growth, but some of this energy is wasted by being 

 transformed into heat which escapes into the surrounding soil. 

 It is this escaping heat which is detected by the thermometer. 



contact with the endosperm 

 for absorption of food from 

 it; r, the primary root. 

 Magnified ahout three times. 

 After Sachs 



