THE STORAGE OF RESERVE MATERIALS 241 
cases, as in fleshy roots, the protein may be dispersed in 
amorphous form in the substance of the protoplasm. 
When protein is stored in the condition of granules 
these are known as aleurone grains. Like starch grains 
they may be deposited all through the substance of the 
seed, or they may occupy definite layers, as they do in the 
cereal grasses (fig. 114). They occur sometimes in the same 
cells as do starch grains, as in the pea or bean (fig. 115). 
In other cases they are found associated with a quantity 
of oil, as in the seed of the castor-oil plant. 
Fie. 116.—Crtts oF Szzp 
oF Lupinus, SHOWING COM- 
MENOING FoRMATION oF 
ALEURONE Grains. (After 
NA AZ t 
cd 
Fic. 116.—Crtts oF EMBRYO oF Rendle.) 
Pea. (After Sachs.) a, nucleus; 6, vacuole; c, 
u, aleurone grains; st, starch grains. originating aleurone grain, 
An instance of the occurrence of aleurone grains of 
some size, but yet of fairly simple composition, is afforded 
by the Lupin, one of the Leguminose. This is of interest 
especially because the origin of the grain can be observed 
and its development traced. In this seed the aleurone 
grains begin to be formed at a very early period of the 
development, just as the growth of the embryo is suffi 
ciently advanced to swell out the seed-coat. The cells of 
the embryo at that period show the protoplasm not sufficient 
in amount to fill each cell, so that a number of spaces or 
vacuoles occur, filled with sap. At certain places small 
projections from the protoplasm may be noticed which are 
of spherical or ovoid shape (fig. 116, c); these gradually 
16 
