7o8 
CHEMICAL PROCESSES IN THE PLANT. 
by oily matter ; and it cannot be doubted that this furnishes the material for the 
growth of the cell-walls when the new organs are being formed. 
To the series of these substances of the same physiological value belongs 
finally cellulose itself, which may also be deposited in considerable quantities as a 
reserve-material, as in the endosperm of the Date, the greater part of the hard kernel 
of which consists of cellulose in the form of the pitted thickening masses of the 
cell-walls. These are dissolved during germination, and the products of their solu- 
tion conveyed to the growing parts of the embryo, where they finally supply the 
material for the growth of the new cell-walls. 
If on the other hand the substances which occur in dormant seeds, bulbs, 
tubers, and other reservoirs of reserve-material, are compared with those which are 
found in the conducting tissues and growing organs of seedlings and young roots — ■ 
which we already know must necessarily be produced from the former, because there 
is no other material which can produce them — it is seen that these reserve-materials 
must undergo repeated Metamorphosis while they are being conveyed to the growing 
organs and are being consumed in the process of growth, and before the permanent 
form of cellulose has been attained. Thus sugar and starch are found temporarily 
in all oily seeds during germination, and are often accumulated in great quantities, 
disappearing when germination is completed. In proportion as they are formed the 
amount of the original oil decreases ; and in proportion as they again disappear the 
quantity of cellulose in the cell-walls increases. In other cases starch is conveyed 
from reservoirs of reserve-material to the growing organs, sugar being at the same 
time formed^; and fine-grained starch is again temporarily formed in the growing 
tissues themselves, disappearing once more with the growth of the cell-walls. This 
temporary formation of starch in the growing tissues themselves is an extremely 
common phenomenon, whether the reservoirs of reserve-material were filled with 
oily matter, inulin, sugar, starch, or cellulose. This transitory starch appears in the 
cells of the parenchyma and epidermis of young organs (only rarely in those of the 
fibro-vascular bundles) after they have become differentiated from the primary meri-. 
stem ; and disappears when the final elongation of the organs is completed, generally 
becoming transformed into sugar (glucose), which in its turn speedily disappears. 
Transitory metamorphoses also take place when the albuminoids stored up in 
the reservoirs of reserve-materials are being transported and consumed^; although 
these metamorphoses cannot be followed by micro-chemical observations, as in the 
^ [The conversion of starch into sugar is effected by means of unorganised ferments ; some of 
these have long been knovi^n, such as Emulsin (in Almonds), Diastase (in Barley), Myrosin (in Black 
Mustard seeds). More recently they have been detected in various plants and parts of plants by 
Kossmann (Journ. Pharm. Chem. (4) 22) and by Krauch (Landwirthsch. Versuchsstat. 23). Von 
Gorup-Besanez has found ferments of this kind in the germinating seeds of Vetches, Hemp and Flax, 
which have also a peptic action (see infrd).^ 
^ [The first stage in the metamorphosis of the reserve-proteids is, doubtless, their conversion 
into peptones, into proteid substances, that is, which are readily soluble in water and which diffuse 
rapidly. This is effected by the action of unorganised ferments. These bodies have been found in 
germinating seeds (v. Gorup-Besanez and Will) and in the secretion of ' carnivorous ' plants such as 
Nepenthes, Drosera, and Darlingtonia. Recently a very active peptic ferment has been found in the 
green fruits of Carica Papaya (Würtz and Bouchet, Le Papain, Comptes rendus, torn. 89, 90, and 91). 
A good resume of our knowledge on the action and distribution of unorganised ferments in plants' 
is given in the second edition (1882) of Husemann's Pflanzenstofle, I. p. 237.] 
