THE FORMATION OF PROTEIDS IN PLANT-CELLS. 
65 
To effect the synthesis of proteids,—especially in the 
last phases—a certain amount of energy is required. This 
energy is procured by respiration. Respiration, however, also 
brings on the partial oxidations necessary for transforming 
glucose into asparagin or aspartic aldehyde. Where respira¬ 
tion is impeded, the protein production will be retarded. It 
is, therefore, not surprising that in the interior of potatoes 
and beets, asparagin is found in company with starch and 
reducing sugar and that the stem of plants contains more as¬ 
paragin than the leaves, as Schulze has found. The stalks 
of Medicago sativa contain 7 times as much asparagin as the 
leaves. Stems and cotyledons of young lupin-plants cultivated 
first in the dark and afterwards 4 weeks in daylight, contained 
18,4% asparagin, the young leaves, however, only 6 %. The 
structure of the leaves and their numerous stomata certainly 
secure a much more energetic respiration than the structure 
of stems, roots and bulbs. As respiration is best supported by 
carbohydrates, it is clear that glucose plays a still more im¬ 
portant rôle in protein formation : it yields chemical energy, and 
as the leaves produce by assimilation of carbonic acid a large 
amount of glucose, it follows that the leaves must be the most 
favorable organs of the plants for the production of proteids. 
The sun-rays are thus indirectly a great supporter of protein- 
formation. Directly, however, no such influence is required, 
as I have shown in experimenting with mould-fungi grown in 
the dark and in diffused day-light; not only was the develop¬ 
ment of the fungus just as energetic in the dark as in the 
light but in some cases it even exceeded the latter. Here 
glucose and glycerin served as organic nutrients. 1 ) 
But while access of air is indispensable for the production 
of asparagin and proteids, such is not the case for the action 
of the enzymes in peptonising and decomposing the reserve 
proteids in the germinating seeds. Palladin has proved that 
shoots,—which remain alive in the absence of air for 24 hours— 
cease to produce asparagin under this condition, 2 ) while the 
production of amido-acids by enzyme is still going on. 
Glucose is in more than one respect highly important for 
1) O. Loew , Biol. Centralbl. io, 584. 
2) Ber. d. Deutsch. Botan. Ges. 6, 205 and 26g. 
