98 GERMINATION OTF SEEDS: SEEDLINGS 
during a germinative period of only 48 hours. That moisture 
is liberated during germination is obvious, for the air in a closed 
germinator often becomes so saturated that moisture precipitates 
on the walls of the germinator. 
When green seeds, green hay, or any plant portions in which 
the cells are quite active are massed together, so that the heat and 
moisture are retained, they often become very warm and moist 
due partly to their own respiration and partly to that of the micro- 
organisms present. The so-called “sweating” of grains in the 
stack or bin and the heating in the bin when the grain becomes 
damp due to leaks are phenomena connected with respiration. 
Summary. — In germination of seeds the following things take 
place: (1) the absorption of water which softens the seed cover- 
ings and acts as a dissolving and transporting medium of foods; 
(2) the secretion of enzymes which digest the foods and assist in 
other processes; (3) the transference of foods by diffusion and 
osmosis; (4) respiration which supplies energy for the elabora- 
tion of foods into plant structures and is accompanied by the ab- 
sorption of oxygen and the production of carbon dioxide, water 
vapor, and some heat; and (5) the growth of the radicle and 
plumule, resulting in the breaking of the seed coverings and the 
establishment of the young plant in the soil and sunlight. 
Testing the Germinative Capacity of Seeds 
The loss in crop and labor when poor seed is used may be so 
serious that no one can afford to plant seeds with a doubtful ger- 
minative capacity. It is not enough for seeds to germinate, but 
they should have vigorous embryos, so that they will germinate 
quickly and thus rapidly pass through the delicate stage in which 
the young plant is likely to be destroyed by insects, Fungi, bad 
weather, and unfavorable soil conditions. 
In testing the germinative capacity, as in determining the im- 
purities of a quantity of seeds, decision is based upon the results 
obtained with a comparatively small number of the seeds as a 
sample. In case of small seeds, such as Oats, Wheat, Barley, and 
Clover, Alfalfa, and Grass seeds, tests are ordinarily made with 
two lots consisting of 200 seeds each and free from impurities. 
In Corn it is customary to use 6 kernels, 2 from near the tip, 
2 from the butt, and 2 from the middle of the ear, with the 
kernels of each pair selected from rows as far apart as possible. 
