16 Richard H. Boerker 
Practically all the accumulated foods in the endosperm must 
be transformed by the action of enzymes, which in turn must 
first be dissolved by water. Starch, which is insoluble in water, 
is converted by means of the enzyme diastase into a soluble sugar. 
Throughout germination the quantity of starch in the seed de- 
creases; the starch grains at first corrode and finally dissolve 
completely. Many albuminoids (simple proteins) are likewise 
insoluble in water and certain soluble albumens cannot diffuse 
through membranes. A pepsin-like enzyme which develops dur- 
ing germination acts upon the albuminoids, transforming them 
into soluble and diffusible forms. Others are changed to crystal- 
loids which after solution diffuse very readily. Fats and oils are 
likewise insoluble. Certain enzymes during germination decom- 
pose oil into its constituents, fatty acids and glycerin, the latter 
easily soluble in water. It is well known that fatty acids when 
set free assist the breaking up of oil in water into very fine drops 
with the formation of an emulsion. 
Heat is important in the germination of the seed in that it may 
accelerate, retard, or even entirely stagnate the processes begun 
by the action of water. It might well be said that the rapidity of 
germination depends to a large extent upon heat, since it has the 
power to modify the action of enzymes. Temperature likewise 
affects the diffusion of liquids. A considerable part of the heat 
used in germination is generated by respiration. This process 
sometimes raises the temperature of the seed as much as 40-50° 
F. above the surrounding temperature. Certain seeds owe their 
ability to germinate at very low temperatures (below freezing) 
to the heat generated during respiration. Certain arctic and 
alpine plants are able to blossom in the snow for this same reason. 
Seeds in water, seeds buried too deep, or seeds surrounded by 
air deprived of oxygen do not germinate even if other conditions 
are favorable. In other words, water and heat are of little avail 
without oxygen. Even before water and heat can act through 
the agency of the enzymes, in many cases another factor must 
come into play to release the enzymes. The latest investigations 
show that the formation of diastase is intimately connected with 
respiration. In a similar manner respiration supplies the energy 
