TRANSLOCATION OF NUTRITIVE MATERIALS = 217 
before it can be restored. To prevent this there should be 
a storage of food close to the seat of its consumption, so 
that, with the awakening need, the required supply may be 
at hand. 
This temporary storage of food must play an important 
part in the metabolism of an organ whose vital processes 
are subject to such numerous and often rapid checks as 
befall young stems, leaves, and roots. Still more necessary 
is it to the floral and fruiting organs during the time of 
their maturing. 
We have seen again that plants set apart particular 
structures for periods of longer quiescence, especially in 
connection with their reproductive processes. Seeds may 
remain for several years without germinating, and they 
generally do so at least for months. The embryo in the 
seed is, however, ready to resume its growth as goon as all 
conditions are favourable. It ig evident that it ig in a 
practically helpless condition with regard to the manufac- 
ture of food, and it must depend upon a previously stored 
supply for the resumption of vital activity. The parent 
plant must, therefore, store quantities of its manufactured 
products in or about the embryo of the seed, stores with 
which it will itself have little further concern, but which 
will be very largely the property of the new organism. The 
same thing is seen to be the case with tubers, bulbs, and 
other organs of vegetative propagation. 
A condition intermediate between the two we have so 
far described is presented by the large fleshy roots and 
rhizomes of biennial and perennial plants. For an illus- 
tration we may consider an ordinary carrot or beetroot. 
Though these plants propagate themselves by the prepara- 
tion of flowers, fruits, and seeds, they do not enter on this 
task during the first year of their lives. During this time 
they are in full foliage, and their constructive processes 
are at their best. They store in their roots a large amount 
of the food so prepared, and these towards the close of the 
first year’s vegetation become enormously swollen by the 
