Germination of Forest Trees 15 
The Germination Process (10, II, 12, 13) 
This period in the life history of the green plant is unique in 
that the organism is independent of an external food supply and 
also of all luminous energy. Germination may be called a period 
of growth without photosynthetic activity, and it terminates at the 
time the accumulated food in the endosperm is more or less ex- 
hausted. During all this time it is without light; it does not 
require it, but lives in total darkness beneath the surface of the 
soil. While the seed has no use for light, it does require water, 
oxygen, and a certain amount of heat in order to germinate suc- 
cessfully. The dependent life of the plant begins at the termina- 
tion of the process of germination, when the first ray of light 
strikes the spreading cotyledons. Light sets the photosynthetic 
mechanism in motion and this marks the beginning of the plant’s 
manufacture of food; henceforth it is dependent upon its en- 
vironment. 
The role of water in the germination process is to aid in the 
transformation of the accumulated nutrient material into food 
that can be used by the germinating embryo. In other words, 
this factor is instrumental in taking this sunken capital and trans- 
forming it into specie for circulation. But water cannot do this 
directly ; it must act through the agency of certain catylists or 
enzymes. ‘These enzymes transform insoluble and indiffusible 
foods into soluble and diffusible ones which in turn move from 
the endosperm to nourish the embryo. 
Water is important to the seed for two reasons; its absence 
determines the seed’s power to live in a dormant condition, which 
is one of its most important properties. If a seed is not dry it 
cannot be preserved ; we cannot secure good seed in a wet autumn. 
The second reason why water is important is because of its 
chemical and mechanical action in germination. Hales at the 
beginning of the eighteenth century showed that the absorption of 
water by seeds is generally accompanied by a considerable mani- 
festation of energy, which takes the form of swelling. Chemically 
water acts as a solvent for the enzymes which render the ac- 
cumulated foods soluble. 
