85 
The Life of the ]Vheai Plant front Seed to Seed. 
In tlie seed begins its independent life, A seed of wheat will 
not grow unless the temperature is 10° above freezing, wliile a 
heat of 104° Fahr. kills it. It germinates most vigorously at 
a temperature of about 80° Falir. 
Supplied with moisture and a suitable temperature, the seed 
begins to swell and soften. In the field the seed gets its mois- 
ture from the soil ; when sown, it should not be placed too deep in 
the’ground, but should be covered just sufficiently to keep it moist. 
The cells of the plantlet contain the living p'ot ooplasm ^ which is 
chemically a nitrogenous substance like the stored-up gluten ; in 
the plantlet it is in a condition of rest, but is capable of resuming 
activity under favourable circumstances. Every active cell in a 
plant is either filled with protoplasm or its walls are lined with 
it. By its agency all the work of the plant is carried on : the 
elements of the food are taken in through root and leaf, are 
manufactured into organised substances, are transmitted to 
where they are needed, and are there built up into the tissues 
of the plant by protoplasm. The starch and other carbo- 
hydrates in the seed supply the material for the formation of 
new cell walls, while the nitrogenous gluten serves to make good 
the waste and to increase the bulk of the protoplasm. The new life 1 
manifests itself by the growth of the minute plant, which soon 
bursts through the skin, first sending down its rootlet and then 
pushing upwards its stem. The whole plantlet escapes from 
the seed except the scutellum, which remains attached to the 
store of food, 2 
A longitudinal section of the seed shows that at this early 
stage of growth a change is taking place in that portion of 
the food store which is next to the plant. With the first 
manifestation of active life, the cells on the surface of the 
scutellum which is applied to the store of food begin to give out 
digestive fluids ; one seizes upon and dissolves the walls of the 
cells ; another, called diastase (the same in nature and action as 
the diastase of the saliva), acts on the starch grains contained 
in the cells, and changes them into grape sugar (glucose ) ; 
and a third, a peptonising fluid (agreeing in its nature and 
action with, trypsine, one of the digestive secretions in the 
alimentary canal), dissolves the gluten grains. The food thus 
prepared is absorbed by the scutellum and transmitted through 
it to the plant, where it is used by the protoplasm to build up 
the growing tissues. In a day or two the rootlets bursITthrough 
their protecting sheaths, and push their way through the soil in 
search of water, which it is their main function to secure for the 
plant. 
In the preparation of malt, the germination of the seed 
is allowed to proceed to this stage. The diastase from the 
