24 Principles of Plant Culture. 
29, Moisture is Essential to Germination. Air-dry 
corn or other seeds will not germinate if kept however long 
in a warm room, whereas vital seeds, that have absorbed 
water until fully swollen, will usually germinate if exposed 
to air of a suitable temperature, under conditions that pre- 
vent their loss of moisture. This shows that a certain 
amount of moisture must be absorbed by the seed before 
germination can take place. Seeds must be nearly or quite 
saturated with water before they will germinate. 
In culture we plant seeds in some moist medium, usually 
the soil, in order that they may absorb moisture and germi- 
nate, and thus develop into new plants. 
30. Warmth is Essential to Germination. Had we 
placed the seed-tester mentioned in paragraph 28 in a re- 
frigerator in which the temperature never rises above 46° F., 
instead of in a warm room, the corn grains would not have 
germinated however long they remained there. This shows 
that a certain degree of warmth is also necessary to germi- 
nation. Without this, the protoplasm of the seed cannot 
assume its active state (13). The lowest (minimum) tem- 
perature at which seeds can germinate varies considerably 
with different species, and so does the temperature at which 
they germinate soonest (optimum) as also the highest (max- 
imum) temperature at which they can germinate. The fol- 
lowing table* shows approximately the minimum, optimum 
and maximum temperatures at which seeds of the species 
named germinate. 
* Compiled from Haberlandt and Sachs. 
ou 
a 
